Dr. Mohammed Abdul Basith is serving as a Professor in the Department of Physics of Bangladesh University of Engineering and Technology (BUET), Dhaka. He has completed BSc Hons. and MSc degrees in Physics from Shahjalal University of Science and Technology, Sylhet. Dr. Basith achieved PhD degree from the Materials and Condensed Matter Physics group, University of Glasgow, UK in 2011. His research interests include transmission electron microscopy (TEM) characterization of patterned ferromagnetic nanostructures by lithographic techniques. At present in BUET, Dr. Basith is working mainly on preparation and characterization of multifunctional nanomaterials for energy-related and spintronic applications. He has published more than 35 research papers in different prestigious journals like Nanoscale, Physical Review Applied, Nature Scientific Reports, Applied Physics Letters, Journal of Applied Physics, Nanotechnology, RSC Advances, Ceramics International, Journal of Alloys and Compounds etc. He is the reviewer of a number of reputed journals published from American Physical Society, American Institute of Physics, Royal Society of Chemistry etc. For the last few years, he has received research grants from different international and national organizations worth 500 thousand USD. In BUET, he has established Nanotechnology Research Laboratory for the synthesis and characterization of nanostructured materials. Since its inception in April 2014, he has been developing advanced facilities in this laboratory under different research projects from home and abroad. Dr. Basith designed a new syllabus titled `Nanophysics’ for the postgraduate students of BUET. The syllabus is designed to cover principles involved in fabrication of nanostructured systems and in measurement of phenomena at nanoscale. He is an activist of BUET career club to deliver lectures that helps young people build meaningful careers. Since 2019, he is serving the National Young Academy of Bangladesh (NYAB) as its first elected president and one of the founding members.
Materials and Condensed Matter Physics
University of Glasgow,UK
Solid State Physics
Bangladesh University of Engineering and Technology (BUET),Dhaka -1000, Bangladesh
Shah Jalal University of Sciences and Technology, Sylhet-3114, Bangladesh
Shah Jalal University of Sciences and Technology, Sylhet-3114, Bangladesh
UNIVERSITY OF GLASGOW, UK - [SEP 2007 - MAR 2011]
Glasgow University funded postgraduate scholarship
BRITISH GOVERNMENT - [SEP 2007 - MAR 2011]
Overseas Research Student Award Scheme (ORSAS) by British Government
BERLIN, GERMANY - [JUL 2007]
Financial assistance provided by the organizing committee for joining in the International colloquium on thin magnetic films and surfaces
ICYS-ICMR And UNIVERSITY OF CALIFORNIA, SANTA BARBABA, USA -
Financial assistance for joining in the ICYS ICMR Summer School 2006 on Nanomaterials,
National Institute of Materials Science, Tsukuba, JAPAN. The nance was provided by the International Centre for Materials Research, University of California, Santa Barbara, USA
ICTP, ITALY - [JAN 2006]
Financial assistance from ICTP, Italy for joining in the Advanced workshop on Recent Developments in Inorganic Materials, The Abdus Salam International Center for Theoretical Physics(ICTP), Trieste, ITALY.
JNCASR, BANGALORE, INDIA And UNIVERSITY OF CALIFORNIA, SANTA
BARBARA, USA - [DEC 2006]
Financial assistance for joining in the JNCASR-ICMR Winter School on the Chemistry of Materials, JNCASR, Bangalore, INDIA. The nance was provided by the International Centre for Materials Research, University of California, Santa Barbara, USA.
ICTP-NCNST-ICTS, CHINA - [AUG 2006]
Financial assistance from ICTP, Italy for joining in the ICTP-NCNST-ICTS Asian /Pacific Regional College on Science at the Nanoscale, Beijing, CHINA.
MINISTRY OF SCIENCE AND ICT, GOVT. OF BANGLADESH - [AUG 2006]
NST fellowship, Ministry of Science and ICT, Government of Bangladesh
KEIO UNIVERSITY, JAPAN - [APR 2007]
Selected for Japanese Government Monbu-Kagakusho Scholarship for PhD programme
NATIONAL TAIWAN UNIVERSITY, TAIWAN - [APR 2007]
Selected for Taiwan International Graduate Scholarship for PhD programme
EHIME UNIVERSITY, JAPAN - [APR 2005]
Selected for Japanese Government Monbu-Kagakusho Scholarship for PhD programme at Ehime University, Japan
NORWEGIAN UNIVERSITY OF SCIENCE AND TECHNOLOGY, NORWAY -
Selected for State Educational Fund for M.Sc programme from Norwegian University of Science and Technology, Norway.
Comparison of the structure-property relationships between sillenite and perovskite phases of Bi0.9Dy0.1FeO3 nanostructures
We explored a comprehensive comparison of the structure–property relationships between sillenite and perovskite phases of Bi0.9Dy0.1FeO3 (BDFO) nanostructures synthesized by hydrothermal (HT) and sol–gel (SG) techniques. The role of sillenite/perovskite phases as well as oxygen vacancies in the magnetic and catalytic properties was analyzed and compared, which to our knowledge, is the first of its kind at the nanometer scale. XRD results revealed the formation of a sillenite dominating phase through the HT synthesis at 160 °C, whereas, the SG method resulted in perovskite bismuth ferrite after calcination at an elevated temperature of 600 °C. Both scanning and transmission electron microscopy imaging demonstrated a mixed nanopowder and rod-like morphology of the materials synthesized by the HT technique, however, semi-spherical particles with a particle size of B100 nm were produced via the SG technique. The XPS analysis revealed that the number of oxygen vacancies was higher in the HT-synthesized BDFO compared to that of the SG-synthesized BDFO. A sharp transition of the HT-synthesized BDFO materials was observed at 43 K, whereas, the SG-synthesized materials revealed a gradual increase in the magnetization with the decrement of temperature from 400 to 5 K without any phase transition. The HT-synthesized BDFO demonstrated a better photocatalytic performance to degrade rhodamine B and colorless antibiotic ciprofloxacin compared to the SG-synthesized BDFO photocatalyst. This comprehensive analysis of the phase-structure, morphology, chemical states, and oxygen vacancies of BDFO materials synthesized under the standard synthesis conditions of two commonly used synthesis techniques might be helpful for researchers to understand the physico-chemical properties of analogous nanostructures for desired applications.
Sol-gel based synthesis to explore structure, magnetic and optical properties of double perovskite Y2FeCrO6 nanoparticles
In this present investigation, nanoparticles of B-site disordered Y2FeCrO6 (YFCO) double perovskite have been successfully synthesized for the first time by optimizing synthesis steps and temperatures of facile sol-gel technique to investigate their structural, magnetic, and optical properties. The Rietveld refinement of the X-ray diffraction pattern of YFCO nanoparticles revealed a single-phase orthorhombic structure with pbnm space group. The average size of the nanoparticles is around 67 ± 15 nm determined by both field emission scanning electron microscopy and transmission electron microscopy imaging. The existence of mixed valence states of Fe and Cr ions was confirmed by X-ray photoelectron spectroscopy which is an indication of the absence of proper B site long range ordering. The temperature dependent magnetization curves demonstrated negative magnetization of this double perovskite material with compensation temperature at around 170 K. The field-dependent magnetic hysteresis loops exhibited the coexistence of weak ferromagnetic and antiferromagnetic domains in YFCO nanoparticles. The exchange bias effect was observed below Néel temperature which is tunable by a cooling magnetic field. The UV–visible spectroscopy ensured that YFCO nanoparticles have a direct band gap of ∼ 1.90 eV, which was further confirmed by steady-state photoluminescence spectroscopy. This B-site disordered YFCO might enhance interest on basic fundamental research on disordered rare-earth and transition metal-based perovskite systems and can be used for spintronics as well as photocatalytic applications because of its favorable magnetic and optical properties.
Nanostructured DyCrO3-rGO for efficient photocatalytic dye degradation and hydrogen generation
Dysprosium chromite (DyCrO3) nanoparticles and dysprosium chromite-reduced graphene oxide (DyCrO3-rGO) nanocomposite were synthesized by using a hydrothermal technique. The rGO incorporated DyCrO3-rGO photocatalyst demonstrated up to 87% efficiency to degrade rhodamine B dye which is higher than those of DyCrO3 and commercial Degussa P25 titania nanoparticles. DyCrO3-rGO also generated approximately 3 times greater amounts of hydrogen via water splitting compared to that produced by the P25 titania nanoparticles. The outcome of this investigation might be helpful for synthesizing rGO-based nanocomposite heterostructures for superior solar energy-driven applications.
CuCo2S4-MoS2 nanocomposite: a novel electrode for high-performance supercapacitors †
Ternary transition metal sulfides have emerged as promising electrode materials for next-generation supercapacitors because of their potential ability to simultaneously ensure high conductivity and stability during electrochemical reactions. In the present investigation, MoS2 incorporated CuCo2S4 nanocomposites have been successfully synthesized using a hydrothermal technique. The structural, morphological, elemental and chemical properties of the prepared CuCo2S4–MoS2 nanocomposite were investigated extensively. High resolution transmission electron microscopy imaging demonstrated the successful synthesis of CuCo2S4–MoS2 nanocomposites. The electrochemical capacitor performance of the nanocomposite has been evaluated both in three-electrode and symmetric two-electrode systems. In the three-electrode cell, a specific capacitance of 820 F g−1 was achieved for the CuCo2S4–MoS2 electrode at a current density of 0.5 A g−1 which is considerably higher than that of the CuCo2S4 electrode (249 F g−1). We observed that the charge storage capacity, conductivity and stability of CuCo2S4 improved significantly due to the incorporation of MoS2. Finally, an asymmetric supercapacitor was fabricated by assembling the CuCo2S4–MoS2 electrode with an activated carbon electrode which demonstrated a large stable working potential window of 1.6 V. Excellent long-term cyclic stability of 89% retention after 1000 galvanostatic charge-discharge cycles was evident. As a solid state device, it delivered a high energy density of 38.22 W h kg−1 at a power density of 400 W kg−1 and lit up one red LED for 170 s, indicating its superiority over the conventional Cu-Co based supercapacitors.
Structural, electrical, and magnetic properties of Ce and Fe doped SrTiO3
Here, we report on the structural, vibrational phonon, electrical, and magnetic properties of undoped strontium titanate SrTiO3, Ce doped Sr1−xCexTiO3, and (Ce, Fe) co-doped Sr1−xCexTi1−yFeyO3 samples synthesized through solid state reaction route. The Rietveld refined powder x-ray diffraction analysis confirmed the cubic Pm-3m phase in our as-synthesized samples. We observed grain size reduction in SrTiO3 from scanning electron micrographs due to the incorporation of Ce and Fe dopants. The sample purity in terms of chemical species identification has been confirmed from energy-dispersive x-ray spectroscopy. The characteristic phonon modes in our samples are identified using room temperature Raman spectroscopy and benchmarked against existing relevant experimental observations. The incorporation of Ce and Fe as substitutional dopants in SrTiO3 unit cell was confirmed from the absence of absorption at 480, 555, 580, and 1635 cm−1 band in Fourier transform infrared spectra. The 3% Ce doping in Sr0.97Ce0.03TiO3 sample may have induced ferroelectric order, whereas the undoped SrTiO3 (STO) revealed lossy paraelectric nature. In the case of (Ce = 3%, Fe = 10%) co-doped Sr0.97Ce0.03Ti0.90Fe0.10O3 sample, we observed ferromagnetic hysteresis with orders of magnitude enhancement in remnant magnetization and coercivity as compared to undoped STO sample. This long range robust ferromagnetic order may have originated from F-center mediated magnetic interaction.
Simple Low Temperature Technique to Synthesize Sillenite Bismuth Ferrite with Promising Photocatalytic Performance
Sillenite-type members of the bismuth ferrite family have demonstrated outstanding potential as novel photocatalysts in environmental remediation such as organic pollutant degradation. This investigation has developed a low temperature one-step hydrothermal technique to fabricate sillenite bismuth ferrite Bi25FeO40 (S-BFO) via co-substitution of 10% Gd and 10% Cr in Bi and Fe sites of BiFeO3, respectively, by tuning hydrothermal reaction temperatures. Rietveld refined X-ray diffraction patterns of the as-synthesized powder materials revealed the formation of S-BFO at a reaction temperature of 120–160 °C. A further increase in the reaction temperature destroyed the desired sillenite structure. With the increase in the reaction temperature from 120 to 160 °C, the morphology of S-BFO gradually changed from irregular shape to spherical powder nanomaterials. The high-resolution TEM imaging demonstrated the polycrystalline nature of the S-BFO(160) nanopowders synthesized at 160 °C. The as-synthesized samples exhibited considerably high absorbance in the visible region of the solar spectrum, with the lowest band gap of 1.76 eV for the sample S-BFO(160). Interestingly, S-BFO(160) exhibited the highest photocatalytic performance under solar irradiation, toward the degradation of rhodamine B and methylene blue dyes owing to homogeneous phase distribution, regular powder-like morphology, lowest band gap, and quenching of electron–hole pair recombination. The photodegradation of a colorless organic pollutant (ciprofloxacin) was also examined to ensure that the degradation is photocatalytic and not dye-sensitized. In summary, Gd and Cr co-doping have proven to be a compelling energy-saving and low-cost approach for the formulation of sillenite-phase bismuth ferrite with promising photocatalytic activity.
Effect of Gd and Y co-doping in BiVO4 photocatalyst for enhanced degradation of methylene blue dye
The development of metal oxide photocatalysts with improved dye degradation efficiency under natural sunlight is in increasing demand due to their superior chemical stability and cost effectiveness. In this context, Gd and Y co-doped BiVO4 having the nominal compositions Bi0.92GdxYyVO4(0.06 ≤ x ≤ 0.08; 0 ≤ y ≤ 0.02) have been synthesized via a surfactant free hydrothermal technique. The structural characterizations by X-ray diffraction, Raman spectroscopy and Fourier transform infrared spectroscopy confirmed a monoclinic to tetragonal phase transition induced by co-doping in BiVO4. High resolution transmission electron microscopy images revealed successful synthesis of Gd and Y co-doped BiVO4 with a very good crystallinity. The steady-state photoluminescence spectroscopy analysis indicated significant suppression of charge carrier recombination in the co-doped samples. Under simulated sunlight, Bi0.92Gd0.07Y0.01VO4 photocatalyst demonstrated 94% degradation of methylene blue dye (MB) within 90 min of irradiation time, which is about 4 times higher than that of pristine BiVO4 photocatalyst. This superior photocatalytic performance may be attributed to the synergistic effect of nanorod like shape of the synthesized materials, negative surface charge, and enhanced charge career lifetime of the Bi0.92Gd0.07Y0.01VO4 photocatalyst.
First-principles study on phase stability and physical properties of B-site ordered Nd2FeCrO6 double perovskite
Here, the first-principles predictions on the structural stability, magnetic behavior and electronic structure of B-site ordered double perovskite Nd2CrFeO6 have been reported. Initially, the ground state of the parent single perovskites NdCrO3 and NdFeO3 have been studied to determine the relevant U value to investigate the properties of Nd2CrFeO6. The thermodynamic, mechanical, and dynamic stability analyses suggest the possibility of the synthesis of Nd2CrFeO6 double perovskite at ambient pressure. The compound shows ferrimagnetic (FiM) nature with 2 μB net magnetic moment and the magnetic ordering temperature has been estimated to be ~265 K. Electronic structure indicates higher probability of direct photon transition over the indirect transition with a band gap of ~1.85 eV. Additional effect of Nd (4f) spin and spin-orbit coupling (SOC) on the band edges have been found to be negligible for this 4f-3d-3d spin system. This first-principles investigation predicts that due to the FiM nature and significantly lower band gap compared to its antiferromagnetic (AFM) parent single perovskites, B-site ordered Nd2CrFeO6 double perovskite could be a promising material for sprintonic and visible-light driven energy device applications.
Highly efficient photocatalytic degradation of hazardous industrial and pharmaceutical pollutants using gadolinium doped BiFeO3 nanoparticles
This investigation highlights the synthesis of an efficient photocatalyst, 10% gadolinium (Gd) doped BiFeO3 (BGFO), via a facile hydrothermal technique at a lower reaction temperature of 160 ∘C and its effective application towards the degradation of industrial effluents, such as rhodamine B (RhB), methylene blue (MB) and pharmaceutical pollutants such as ciprofloxacin (CIP), levofloxacin (LFX) under solar irradiation. The successful fabrication of the photocatalyst was confirmed by the Rietveld refined powder X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy analyses. The high-resolution transmission electron microscope imaging demonstrated the formation of nanoparticles with excellent morphology and very good crystallinity. The optical characterizations revealed a reduction in the optical bandgap from 1.95 to 1.18 eV, as well as effective suppression of electron-hole pair recombination in the BGFO sample. Notably, the photocatalyst BGFO demonstrated 96% and 97% degradation of RhB and MB within 240 and 180 min of solar irradiation, respectively. Moreover, the photodegradation of colorless organic contaminants CIP and LFX was also examined to evaluate the photosensitization properties. Interestingly, about 80% and 79% degradation of CIP and LFX was obtained within 240 min of solar irradiation. The enhanced photocatalytic activities of BGFO could be attributed to the excellent morphology, good crystallinity, increased optical absorption, and effective separation of the photogenerated charge carriers. Additionally, based on the band structures, a plausible mechanism was proposed to comprehend the rationale behind the influential photocatalytic performance of the synthesized nanoparticles to explore their potential towards the future of wastewater treatment on an industrial scale.
Sol-gel synthesized double perovskite Gd2FeCrO6 nanoparticles: Structural, magnetic and optical properties
Lead-free double perovskites are overtaking single perovskites as solar harvesting materials due to their superior stability, excellent catalytic efficiency and minimal toxicity. In this investigation, we have synthesized double perovskite Gd2FeCrO6 (GFCO) nanoparticles for the first time via a facile sol-gel technique to investigate their structural, magnetic and optical properties. The double perovskite GFCO crystallized in monoclinic structure with P21/n space group. The Fe/Cr-O bond length was calculated as ~ 1.95 Å from the Raman spectrum which was consistent with the value, ~ 1.99 Å obtained from X-ray diffraction analysis. The average size of the nanoparticles was determined to be ~ 70 nm by both field emission scanning electron microscopy and transmission electron microscopy. The existence of mixed valence states of Fe and Cr was confirmed by X-ray photoelectron spectroscopy. The zero field cooled (ZFC) and field cooled (FC) curves largely diverged below 20 K. A downturn was observed in the ZFC curve at 15 K which corresponds to an antiferromagnetic, Néel transition. The narrow magnetic hysteresis loop recorded at 5 K was nearly saturated and demonstrated an asymmetric shift along the magnetic field axis indicating the concurrence of ferromagnetic and antiferromagnetic domains in GFCO nanoparticles. The UV–visible and photoluminescence spectroscopic analyses unveiled the semiconducting nature of nanostructured GFCO with an optical band gap of 2.0 eV. The as-synthesized thermally stable lead-free GFCO semiconductor might be a potential perovskite material to be employed in photocatalytic and related solar energy applications due to its ability to absorb the visible spectrum of the solar light.
Nanostructured LaFeO3-MoS2 for efficient photodegradation and photocatalytic hydrogen evolution
Fabrication of heterogeneous photocatalysts has received increasing research interest due to their potential applications for the degradation of organic pollutants in wastewater and evolution of carbon-free hydrogen fuel via water splitting. Here, we report the photodegradation and photocatalytic hydrogen generation abilities of nanostructured LaFeO3-MoS2 photocatalyst synthesized by facile hydrothermal technique. Prior to conducting photocatalytic experiments, structural, morphological and optical properties of the nanocomposite were extensively investigated using X-ray diffraction analysis, field emission scanning electron microscopy and UV-visible spectroscopy, respectively. Nanostructured LaFeO3-MoS2 photodegraded ~96% of rhodamine B dye within only 150 minutes which is considerably higher than that of LaFeO3 and commercial Degussa P25 titania nanoparticles. The LaFeO3-MoS2 nanocomposite also exhibited significantly enhanced photocatalytic efficiency in the decomposition of a colorless probe pollutant, ciprofloxacin eliminating the possibility of the dye-sensitization effect. Moreover, LaFeO3-MoS2 demonstrated superior photocatalytic activity towards solar hydrogen evolution via water splitting. Considering the band structures and contribution of reactive species, a direct Z-scheme photocatalytic mechanism is proposed to rationalize the superior photocatalytic behavior of LaFeO3-MoS2 nanocomposite.
First-principles calculation of the electronic and optical properties of Gd2FeCrO6 double perovskite: Effect of Hubbard U parameter
We have synthesized Gd2FeCrO6 (GFCO) double perovskite which crystallized in monoclinic structure with P21/n space group. The UV-visible and photoluminescence spectroscopic analyses confirmed its direct band gap semiconducting nature. Here, by employing experimentally obtained structural parameters in first-principles calculation, we have reported the spin-polarized electronic band structure, charge carrier effective masses, density of states, electronic charge density distribution and optical absorption property of this newly synthesized GFCO double perovskite. Moreover, the effects of on-site d-d Coulomb interaction energy (Ueff) on the electronic and optical properties were investigated by applying a range of Hubbard Ueff parameter from 0 to 6 eV to the Fe-3d and Cr-3d orbitals within the generalized gradient approximation (GGA) and GGA+U methods. Notably, when we applied Ueff in the range of 1 to 5 eV, both the up-spin and down-spin band structures were observed to be direct. The charge carrier effective masses were also found to enhance gradually from Ueff = 1 eV to 5 eV, however, these values were anomalous for Ueff = 0 and 6 eV. These results suggest that Ueff should be limited within the range of 1 to 5 eV to calculate the structural, electronic and optical properties of GFCO double perovskite. Finally we observed that considering Ueff = 3 eV, the theoretically calculated optical band gap ∼1.99 eV matched well with the experimentally obtained value ∼2.0 eV. The outcomes of our finding imply that the Ueff value of 3 eV most accurately localized the Fe-3d and Cr-3d orbitals of GFCO keeping the effect of self-interaction error from the other orbitals almost negligible. Therefore, we may recommend Ueff = 3 eV for first-principles calculation of the electronic and optical properties of GFCO double perovskite that might have potential in photocatalytic and related solar energy applications.
Frequency and temperature dependent electric polarization, relaxation, and transport properties of Mo and W doped BaTiO3
In this article, we report the structural, dielectric, electronic, and transport properties of Mo and W doped BaTiO3 ceramic. The BaTiO3 (BTO), BaTi0.85Mo0.15O3 (BTMO), and BaTi0.85W0.15O3 (BTWO) samples were prepared by double sintering ceramic technique. The X-ray diffraction patterns confirmed the tetragonal phase of the perovskite structure with the P4mm space group including some extra phases in BTMO and BTWO. A relaxation peak in the real part of electric modulus (M’’)is observed for BTO and BTMO at 3kHz. The dielectric constants, (εr' , εr'') and loss tangent (tanδ) for all samples were measured from 300 K to 450 K under the application of 100kHz electric field and temperature dependent dielectric anomalies ensure a ferroelectric (tetragonal) to paraelectric (cubic) phase transition in all samples. BTO and BTMO crystals display between normal ferroelectric and ideal relaxor behavior while BTWO crystal approaches to ideal relaxor ferroelectric behavior identified as canonical relaxor. Moreover, solid–liquid state anisotropy during the phase transition in all samples has been illustrated in terms of Fr ̈ohlich entropy. Apart from this, in BTO and BTWO samples, the conduction mechanism is highly dominated by the frequency of applied field compared to BTMO sample. Moreover, all studied samples exhibit semiconducting behavior with positive temperature coefficient of resistance (PTCR) effect in between 300 K and 450 K. The BTMO sample with maximum PTCR peak (2.9%/K at 415K) may find suitability for temperature controlled device application.
Photocatalytic water splitting ability of Fe/MgO-rGO nanocomposites towards hydrogen evolution
Photocatalytic water splitting has greatly stimulated as an ideal technique for producing hydrogen (H2) fuel by employing two renewable sources, i.e., water and solar energy. Here, we have adopted a facile hydrothermal approach for the successful synthesis of reduced graphene oxide (rGO) incorporated Fe/MgO nanocomposites followed by thermal treatment at inert atmosphere to investigate their ability for photodegradation and photocatalytic hydrogen evolution via water splitting. Transmission Electron Microscopy images of Fe/ MgO-rGO nanocomposite ensured the distribution of Fe/MgO nanoparticles throughout rGO sheets. Notably, all rGO supported nanocomposites, especially the one, thermally treated at 500 oC at Argon (Ar) atmosphere has demonstrated significantly higher photocatalytic efficiency towards the photodegradation of a toxic textile dye, rhodamine B, than pristine MgO and commercially available Degussa P25 titania nanoparticles as well as other composites. Under solar irradiation, Fe/MgO-rGO (500) nanocomposite exhibited 86% degradation of rhodamine B dye and generated almost four times higher H2 via photocatalytic water splitting compared to commercially available P25 titania nanoparticles. This promising photocatalytic ability of the Fe/MgO-rGO(500) nanocomposite can be attributed to the improved morphological and surface features due to heat treatment at inert atmosphere as well as escalated charge carrier separation with increased light absorption capacity imputed to rGO incorporation.
Lead-free CsSnCl3 perovskite nanocrystals: rapid synthesis, experimental characterization and DFT simulations
Lead-free metal halide perovskites have attracted great attention as light harvesters due to their promising optoelectronic and photovoltaic properties. In this investigation, we have successfully synthesized thermally stable cubic phase cesium tin chloride (CsSnCl3) perovskite nanocrystals with improved surface morphology by adopting a rapid hot-injection technique. The excellent crystalline quality of these cubic shaped nanocrystals was confirmed by high-resolution transmission electron microscopy imaging. The binding of organic ligands on the surface of the sample was identified and characterized using nuclear magnetic resonance spectroscopy. UV-visible spectroscopy confirmed that the CsSnCl3 nanocrystals have a direct band gap of ∼2.98 eV, which was further confirmed using steady-state photoluminescence spectroscopy. The band edge positions calculated using the Mulliken electronegativity approach predicted the potential photocatalytic capability of the as-prepared nanocrystals, which was then experimentally corroborated through the photodegradation of rhodamine-B dye under both visible and UV-visible irradiation. Our theoretical calculations employing experimentally obtained structural parameters within the generalized gradient approximation (GGA) and GGA+U methods demonstrated a 90% accurate estimation of the experimentally observed optical band gap when Ueff = 6 eV was considered. The ratio of the effective mass of the hole and electron expressed as was also calculated for Ueff = 6 eV. Based on this theoretical calculation and experimental observation of the photocatalytic performance of CsSnCl3 nanocrystals, we have proposed a rational interpretation of the “D” value. We think that a “D” value of either much smaller or much larger than 1 is an indication of the low recombination rate of the photogenerated electron–hole pairs and the high photocatalytic efficiency of the photocatalyst. We believe that this comprehensive investigation might be helpful for the large-scale synthesis of thermally stable cubic CsSnCl3 nanocrystals and also for a greater understanding of their potential in photocatalytic, photovoltaic and other prominent optoelectronic applications.
Room temperature ferroic orders in Zr and (Zr, Ni) doped SrTiO3
We synthesized strontium titanate SrTiO3 (STO), Zr doped Sr1−xZrxTiO3 and (Zr, Ni) co-doped Sr1−xZrxTi1−yNiyO3 samples using solid-state reaction technique to report their structural, electrical, and magnetic properties. The cubic Pm-3m phase of the synthesized samples has been confirmed using Rietveld analysis of the powder X-ray diffraction pattern. The grain size of the synthesized materials was reduced significantly due to Zr doping as well as (Zr, Ni) co-doping in STO. The chemical species of the samples were identified using energy-dispersive X-ray spectroscopy (EDX). The Zr and Ni dopants’ homogeneity were confirmed from EDX mapping to negate spurious ferroic order due to dopant segregation. We observed forbidden first-order Raman scattering at 148, 547 and 797 cm−1 which may indicate nominal loss of inversion symmetry in cubic STO. The absence of absorption at 500 cm−1 and within 600–700 cm−1 band in Fourier Transform Infrared spectra corroborates Zr and Ni as substitutional dopants in our samples. Due to 4% Zr doping in Sr0.96Zr0.04TiO3 sample dielectric constant, remnant electric polarization, remnant magnetization, and coercivity were increased. Notably, in the case of 4% Zr and 10% Ni co-doping we have observed clearly the existence of both FE and FM hysteresis loops in the Sr0.96Zr0.04Ti0.90Ni0.10O3 sample. In this co-doped sample, the remnant magnetization and coercivity were increased by ∼1 and ∼2 orders of magnitude respectively as compared to those of undoped STO. The coexistence of FE and FM orders in (Zr, Ni) co-doped STO might have the potential for interesting multiferroic applications.
Thermal stability of the crystallographic structure of nanocrystalline Nd0.7Sr0.3MnO3 manganite with enhanced magnetic properties
We report the effect of temperature on the crystallographic structure and magnetic properties of ultrasonically prepared nanostructured Nd0.7Sr0.3MnO3 perovskite manganite. The crystal structure of as-synthesized nanoparticles remains unaltered over a wide scanning temperature range. Temperature dependent magnetization measurements demonstrate that the Curie temperature (Tc) of Nd0.7Sr0.3MnO3 nanoparticles is in the range of 211 K–220 K under largely varying applied magnetic fields. Below Tc, the soft ferromagnetic nature of these nanoparticles is confirmed by the field-dependent magnetization measurements. The absence of the charge-ordered state is also revealed in this nanomanganite down to 20 K, which is strikingly different from analogous Nd–Sr based nanocrystals. The experimentally observed effective paramagnetic moment and saturation magnetic moment have matched quite well with the values calculated theoretically. The Tc values up to a temperature of 220 K, nearly perfect ferromagnetically ordered Mn ions below Tc, high saturation magnetization, and magnetic softness of synthesized nanostructured Nd0.7Sr0.3MnO3 manganite can be associated with their good crystallinity as well as the nominal internal and surface disorder effect owing to intermediate particle size (∼75 nm to 150 nm). Our investigation elucidates the promising potential of nanocrystalline Nd0.7Sr0.3MnO3 particles for numerous technological applications.
From bulk to nano: A comparative investigation of structural, ferroelectric and magnetic properties of Sm and Ti co-doped BiFeO3 multiferroics
In this investigation, multiferroic bulk ceramic materials with nominal compositions Bi1-xSmxFe1-yTiyO3 (x, y = 0.00, 0.03, 0.06) are synthesized by conventional solid-state reaction technique. Their corresponding nanoparticles are fabricated from these bulk powder materials using cost-effective ultrasonication method. Then, the structural and multiferroic properties of the synthesized nanoparticles and their bulk-counterparts are compared. The X-ray diffraction patterns of 6% Sm-Ti co-substituted BiFeO3nanoparticles as well as their bulk powder materials confirm rhombohedral to orthorhombic structural phase transition. Dynamic Light Scattering analysis (DLS) demonstrates the formation of particles with a size in the range of 10–100 nm for the 6% Sm-Ti co-substituted BiFeO3 sample. The fabricated nanoparticles of this particular composition also exhibit suppressed leakage current density and enhanced ferroelectric behavior. These nanoparticles also demonstrate improved ferromagnetic behavior compared to their bulk counterparts. Thus, the present investigation illustrates the impact of Sm and Ti as co-doping elements with 6% concentration in BiFeO3 nanoparticles with improved structural and multiferroic properties required for practical applications.
Low temperature synthesis of BiFeO3 nanoparticles with enhanced magnetization and promising photocatalytic performance in dye degradation and hydrogen evolution
Enhanced photocatalytic dye degradation and hydrogen production ability of Bi25FeO40-rGO nanocomposite and mechanism insight
Sol-gel synthesis of DyCrO3 and 10% Fe-doped DyCrO3 nanoparticles with enhanced photocatalytic hydrogen production abilities
Enhanced multiferroism in Gd-doped BiMn2O5 ceramics.
Determination of optical band gap of powder form nanomaterials with improved accuracy
Temperature-dependent phase transition and comparative investigation on enhanced magnetic and optical properties between sillenite and perovskite bismuth ferrite-rGO nanocomposites
Simple sonofragmentation approach for synthesis of NiFe nanoalloy with tunable magnetization
Dy doped BiFeO3: A bulk ceramic with improved multiferroic properties compared to nano counterparts
The synthesis as well as structural, multiferroic and optical characterization of Dy doped BiFeO3 multiferroic ceramic are presented. Bulk polycrystalline Bi0.9Dy0.1FeO3 sample is synthesized by solid state reaction, while their nano counterparts are prepared using ultrasonic probe sonication technique. Significant improvement of phase purity in the as synthesized samples is observed after the doping of Dy both in bulk Bi0.9Dy0.1FeO3 sample and corresponding nanoparticles as evidenced from Rietveld refinement. Magnetization measurements using SQUID magnetometer exhibit enhanced magnetic properties for Dy doped bulk Bi0.9Dy0.1FeO3 ceramic compared to their nanostructured counterparts as well as undoped BiFeO3. Within the applied field range, saturation polarization is observed for Bi0.9Dy0.1FeO3 bulk ceramic only. As a result, intrinsic ferroelectric behavior is obtained just for this sample. Optical bandgap measurements reveal lower bandgap for Dy doped bulk Bi0.9Dy0.1FeO3 ceramic compared to that of corresponding nanoparticles and undoped BiFeO3. The outcome of this investigation demonstrates the potential of Dy as a doping element in BiFeO3 that provides a bulk ceramic material with improved multiferroic and optical properties compared to those of corresponding nanoparticles which involve rigorous synthesis procedure.
Preparation of high crystalline nanoparticles of rare-earth based complex perovskites and comparison of their structural and magnetic properties with bulk counterparts
A simple route to prepare Gd0.7Sr0.3MnO3 nanoparticles by ultrasonication of their bulk powder materials is presented in this article. For comparison, Gd0.7Sr0.3MnO3 nanoparticles are also prepared by ball milling. The prepared samples are characterized by x-ray diffraction (XRD), field emission scanning electron microscope (FESEM), energy dispersive x-ray (EDX), x-ray photoelectron spectroscope (XPS), and superconducting quantum interference device (SQUID) magnetometer. XRD Rietveld analysis is carried out extensively for the determination of crystallographic parameters and the amount of crystalline and amorphous phases. FESEM images demonstrate the formation of nanoparticles with average particle size in the range of 50–100 nm for both ultrasonication and 4 h (h) of ball milling. The bulk materials and nanoparticles synthesized by both ultrasonication and 4 h ball milling exhibit a paramagnetic to spin-glass transition. However, nanoparticles synthesized by 8 h and 12 h ball milling do not reveal any phase transition, rather show an upturn of magnetization at low temperature. The degradation of the magnetic properties in ball milled nanoparticles may be associated with amorphization of the nanoparticles due to ball milling particularly for milling time exceeding 8 h. This investigation demonstrates the potential of ultrasonication as a simple route to prepare high crystalline rare-earth based manganite nanoparticles with improved control compared to the traditional ball milling technique.
Effect of Strontium substitution on the structural and magnetic properties of La1.8Sr0.2MMnO6 (M = Ni, Co) layered manganites
Sr-substituted perovskites, La1.8Sr0.2MMnO6 (M = Ni, Co), were synthesized using the solid-state reaction technique to present a systematic study on their morphological, structural and magnetic properties. The average grain size of the as-prepared La1.8Sr0.2MMnO6 samples are in the range of 0.2–0.7 µm and those for La1.8Sr0.2CoMnO6 manganites are 0.1–2.8 μm, which is significantly less than that of unsubstituted La2NiMnO6 (LNMO) and La2CoMnO6 (LCMO) manganites. The XPS analysis enlightened about phase purity, binding energy and oxygen vacancy of La1.8Sr0.2MMnO6 manganites. The Sr-substituted LNMO has revealed a sharp ferromagnetic to paramagnetic phase transition at 160 ± 2 K, which is about 120 K less than that of parent LNMO. The Sr-substituted LCMO exhibited such a transition at 220 ± 2 K, which is 8 K less than that of parent LCMO. The temperature-dependent magnetization measurements suggest that the effect of Sr on the transition temperature in LNMO is more significant than that of LCMO.
The 10% Gd and Ti co-doped BiFeO3: A promising multiferroic material
In this investigation, undoped BiFeO3, Gd doped Bi0.9Gd0.1FeO3, and Gd-Ti co-doped Bi0.9Gd0.1Fe1-xTixO3 (x = 0.10, 0.20) materials were synthesized to report their multiferroic properties. The structural analysis and phase identification of these multiferroic ceramics were performed using Rietveld refinement. The Rietveld analysis has confirmed the high phase purity of the 10% Gd-Ti co-doped Bi0.9Gd0.1Fe0.9Ti0.1O3 sample compared to that of other compositions under investigation. The major phase of this particular composition is of rhombohedral R3c type structure (wt% >99%) with negligible amount of impurity phases. In terms of characterization, we address magnetic properties of this co-doped ceramic system by applying substantially higher magnetic fields than that applied in previously reported investigations. The dependence of temperature and maximum applied magnetic fields on their magnetization behavior have also been investigated. Additionally, the leakage current density has been measured to explore its effect on the ferroelectric properties of this multiferroic system. The outcome of this investigation suggests that the substitution of 10% Gd and Ti in place of Bi and Fe, respectively, in BiFeO3 significantly enhances its multiferroic properties. The improved properties of this specific composition is associated with homogeneous reduced grain size, significant suppression of impurity phases and reduction in leakage current density which is further asserted by polarization vs. electric field hysteresis loop measurements.
Saturation magnetization and band gap tuning in BiFeO3 nanoparticles via co-substitution of Gd and Mn
In this investigation, Gd and Mn co-doped Bi0.85Gd0.15Fe1−xMnxO3 (x = 0.0–0.15) nanoparticles have been prepared to report the influence of co-substitution on their structural, optical, magnetic and electrical properties. Due to simultaneous substitution of Gd and Mn in BiFeO3, the crystal structure has been modified from rhombohedral (R3c) to orthorhombic (Pn21a) and the FeOFe bond angle and FeO bond length have been changed. For Mn doping up to 10% in Bi0.85Gd0.15Fe1−xMnxO3 nanoparticles, the saturation magnetization (Ms) has been enhanced significantly, however, for a further increase of doping up to 15%, the Mshas started to reduce again. The co-substitution of Gd and Mn in BiFeO3nanoparticles also demonstrates a strong reduction in the optical band gap energy and electrical resistivity compared to that of undoped BiFeO3.
Large difference between the magnetic properties of Ba and Ti co-doped BiFeO3 bulk materials and their corresponding nanoparticles prepared by ultrasonication
The ceramic pellets of the nominal compositions Bi0.7Ba0.3Fe1−x Ti x O3 (x = 0.00–0.20) were prepared initially by standard solid state reaction technique. The pellets were then ground into micrometer-sized powders and mixed with isopropanol in an ultrasonic bath to prepare nanoparticles. The x-ray diffraction patterns demonstrate the presence of a significant number of impurity phases in bulk powder materials. Interestingly, these secondary phases were completely removed due to the sonication of these bulk powder materials for 60 minutes. The field and temperature dependent magnetization measurements exhibited significant difference between the magnetic properties of the bulk materials and their corresponding nanoparticles. We anticipate that the large difference in the magnetic behavior may be associated with the presence and absence of secondary impurity phases in the bulk materials and their corresponding nanoparticles, respectively. The leakage current density of the bulk materials was also found to suppress in the ultrasonically prepared nanoparticles compared to that of bulk counterparts.
Size dependent magnetic and electrical properties of Ba-doped nanocrystalline BiFeO3
Improvement in magnetic and electrical properties of multiferroic BiFeO3 in conjunction with their dependence on particle size is crucial due to its potential applications in multifunctional miniaturized devices. In this investigation, we report a study on particle size dependent structural, magnetic and electrical properties of sol-gel derived Bi0.9Ba0.1FeO3nanoparticles of different sizes ranging from ∼ 12 to 49 nm. The substitution of Bi by Ba significantly suppresses oxygen vacancies, reduces leakage current density and Fe2+ state. An improvement in both magnetic and electrical properties is observed for 10 % Ba-doped BiFeO3 nanoparticles compared to its undoped counterpart. The saturation magnetization of Bi0.9Ba0.1FeO3 nanoparticles increase with reducing particle size in contrast with a decreasing trend of ferroelectric polarization. Moreover, a first order metamagnetic transition is noticed for ∼ 49 nm Bi0.9Ba0.1FeO3 nanoparticles which disappeared with decreasing particle size. The observed strong size dependent multiferroic properties are attributed to the complex interaction between vacancy induced crystallographic defects, multiple valence states of Fe, uncompensated surface spins, crystallographic distortion and suppression of spiral spin cycloid of BiFeO3.
Anomalous coercivity enhancement with temperature and tunable exchange bias in Gd and Ti co-doped BiFeO3 multiferroics
Lorentz TEM imaging of magnetic hybrid structures embedded in a soft magnetic matrix.
Tunable exchange bias effect in magnetic Bi0.9Gd0.1Fe0.9Ti0.1O3 nanoparticles at temperatures up to 250 K.
Engineering magnetic domain-wall structure in permalloy nanowires.
Magneto-structural coupling in NixZn1-xCr2O4.
Simple top-down preparation of magnetic Bi0.9Gd0.1Fe1-xTixO3 nanoparticles by ultrasonication of mutiferroic bulk material.
Room temperature dielectric and magnetic properties of Gd and Ti co-doped BiFeO3 ceramics.
Reproducible domain wall pinning by linear non-topographic features in a ferromagnetic nanowire.
Direct comparison of domain wall behavior in Permalloy nanowires patterned by electron beam lithography and focused ion beam milling.
The microstructure, high performance magnetic hardness and magnetic after-effect of an α- FeCo/Pr2Fe14B nanocomposite magnet with low Pr concentration.
A study on the Carrier Recombination in the Back Surface for the Performance of Crystalline Si-Solar Cell.
Temperature features of magnetoresistance of layered manganite La2Sm0.4Sr0.6Mn2O7.
Effect of MnO2 layers on the transport properties of Lan-nxCa1+nxMnn-yCryO7 (n =2, 3; x = 0.3; y = 0.075, 0.15, 0.3).
Observation of high Tc in the bi-layered La2SmxSr1-xMn2O7 perovskite.
Scientific Literacy and Eco materials Research for Global Mankind.
Materials Science Education and Research in Bangladesh: Present Trends and Future Perspective for Industrial Development.
Magnetoresistive Properties of Gd Doped Lanthanum Strontium Manganites.
Magnetoresistive Properties of La2-xHoxBa1-yCayMn2O7 Manganites.
A study of Shielding effectiveness in various materials using PHOTCOEF.
Investigation of the Dose Deposition Profiles in Various Materials Using PHOTCOEF.
Strong Ultraviolet Radiation Effects on German Made CsI (Tl) Crystal.
Synthesis of Iron-Magnesium Oxide-Reduced Graphene Oxide Nanocomposite and Investigation of its Photocatalytic Activity for Dye Degradation and Solar Hydrogen Generation.
Towards the Development of Nanotechnology Research Laboratory, BUET.
Hydrothermal Route: An Excellent Synthesis Process for Producing High Phase Pure Bismuth Ferrite Nanoparticles at Low Temperature.
Structural and Optical Properties of BiFeO3: A Combined Experimental and Theoretical Investigation.
Dy Doped CoFe2O4 Nanoparticles Prepared at Ar atmosphere for Photocatalytic Applications.
Effect of 10% Fe-doping on the Photocatalytic Hydrogen Production Ability of Sol-gel Synthesized DyCrO3 Nanoparticles.
Improved Morphology and Enhanced Multiferroicity in Gd-doped BiMn2O5 Ceramics.
Modification of Beer-Lambert law and Kubelka-Munk function to accurately measure optical band gap of powder-form nanomaterials.
Synthesis of Magnetic Binary Alloy Nanoparticles by Sonofragmentation Process.
Low Temperature Synthesis of 10% Dy doped BiFeO3 Nanoparticles by Cost Effective Hydrothermal Technique and Comparison of its Structural and Magnetic Properties with Bulk Counterpart.
A Comparative Investigation on Enriched Photocatalytic Properties between Sillenite and Perovskite Bismuth Ferrite-rGO Nanocomposites.
Preparation of Bi0.9Y0.1 FeO3 Nanoparticles and Investigation of their Multiferroic and Photocatalytic Properties.
Preparation and Investigation of the Structural and Magnetic Properties of Nd0.7Sr0.3MnO3 Nanoparticles and their Bulk Counterparts.
Effect of Heat Treatment at Inert Atmosphere on the Structural and Optical Properties of Gd doped BiFeO3-rGO Nanocomposite.
Optimization of the Oxidation Temperature of Graphene Oxide.
A simple route to prepare Gd0.7Sr0.3MnO3 nanoparticles from their bulk powder materials.
Facile hydrothermal synthesis of bismuth ferrite-reduced graphene oxide nanocomposites and investigation of their crystallographic phase transition.
Multiferroic properties of Gd Doped BiFeO3 Nanoparticles Prepared By Sol-Gel Method.
Sol-Gel synthesis of DyCrO3 nanoparticles as novel photocatalysts.
Enhancement in The Multiferroic Properties of Gd And Mn Co-Doped BiFeO3 Ceramics.
A Promising Bulk Multiferroic Material: The 10% Gd And Ti Co-Doped BiFeO3.
Effect of Ti doping in BiFeO3 multiferroics.
Rietveld analysis and magnetic properties of Nd0.7Sr0.3MnO3 manganites.
Preparation of Bi25FeO40-rGO nanocomposites via a facile hydrothermal route and investigation of their magnetic and optical properties.
Effect of synthesis route on the structural, magnetic and optical properties of BiFeO3: a comparative study between solid state and hydrothermal methods.
Enhanced coercivity and tunable exchange bias in Gd and Ti co-doped BiFeO3 multiferroics.
Dy doped BiFeO3: A promising destination in the quest of a ceramic with improved bulk multiferroic properties compared to those of its corresponding nanoparticles.
Enhanced Multiferroism in Li-doped Bismuth Ferrite.
Dy doped BiFeO3: A multiferroic with bulk structural and ferroelectric properties comparable with nano counterparts.
Assessment of Effectiveness of Hematite and Bismuth Ferrite Nanoparticles as Adsorbents for Arsenic Removal.
Multiferroic properties of Li doped BiFeO3 nanoparticles prepared by ultrasonication.
Properties of Nd and Co co-doped BiFeO3 Ceramics at Room Temperature.
Preparation and Investigation of the Structural and Magnetic Properties of Perovskite Manganites La1.8Sr0.2CoMnO6.
Simple Top-Down Preparation of Magnetic Bi0.9Gd0.1Fe1-xTixO3 Nanoparticles by Ultrasonication of Multiferroic Bulk Material.
Comparison of the Magnetic Properties of Gd0.7Sr0.3MnO3 Nanoparticles and their Bulk Counterparts.
Temperature Dependent Dielectric and Magnetic Properties of Gd and Ti co-Doped BiFeO3 Ceramics.
Dielectric and Magnetic Properties of Nd and Co co-Doped BiFeO3 Ceramics at Room Temperature.
Exploring exchange bias effect in Gd and Ti co-doped BiFeO3 multiferroics.
Temperature dependent dielectric and magnetic properties of Bi1-xGdxMnO3 ceramics .
Structural, dielectric and magnetic properties of Gd and Ti co-doped BiFeO3 multiferroics.
Micromagnetics simulation of the edge profiles of permalloy (Ni80Fe20) nanowires.
Evidence of ferromagnetic transition in antiferromagnetic LaMnO20 due to size reduction .
Evolution of CoFe2O4 nanoparticles and strong correlation of grain size with physical properties .
Detection of Magnetic labels using Planar Hall Resistance Sensor.
Reproducible pinning/depinning of magnetic domain wall by linear non-topographic features in a ferromagnetic nanowire.
Controlling domain walls by non-topographic pinning features in a permalloy nanowire structure.
Analysis of magnetic structure in nanopatterned thin films.
Magnetisation reversal processes in ion irradiated magnetic stripes.
Ion induced pinning sites to control domain walls in planar nanowires.
Electron transport properties of Fe- doped bi-layered managnites La1.6Dy0.2Sr1.2Mn2-xFexO7
Magnetoresistance in Double Layered Perovskite Manganites.
A Study of the Electrical Properties of Silicon Dioxide (SiO2) Thin Films.
Exploring Gd and Ti co-doped BiFeO3 Multiferroics for Spintronic and Energy Applications.