Abstract

Influence of Dy content on the microstructure and magnetic properties of Mg Cu–Zn ferrites having the compositions Mg0.4Cu0.2Zn0.4DyxFe2-xO4 (where x = 0.0, 0.01, 0.02, 0.03, and 0.04) is reported in this study. An x-ray diffraction pattern has shown the single-phase cubic spinel structure for x ≤ 0.02, while a small peak of DyFeO3 coexists with the cubic spinel structure for x > 0.02. A microstructural study shows that the grain growth of Mg–Cu–Zn ferrites depends on the Dy content. It is seen that the average grain size is found to be larger at x = 0.02, which could be ascribed to the densification of the sample. The complex magnetic permeability measurement has shown that the enhancement of permeability is evidenced by the amount of Dy content. The saturation magnetization (Ms) and coercivity (Hc) have been observed for all the studied samples. It has been dem onstrated that the magnetic softness property of the materials (for x = 0.02) has been improved due to the smaller value of Hc, which is also correlated to the grain size. Frequency-dependent dielectric constant and ac conductivity of the prepared samples have been investigated at 300 K. The dielectric property of the samples has shown dispersive behavior following the Maxwell–Wagner type of polariza tion. The Cole–Cole plots have exhibited a single semicircular arc for x ≤ 0.03, which indicates that the conduction mechanism occurred through the grain effect. An enhancement of the magnetic softness property has been improved due to the lower value of Hc along with the larger value of the initial permeability at x = 0.02. It is inferred that the composition with Mg0.4Cu0.2Zn0.4Dy0.02Fe1.98O4 will be useful in an inductor material in high quality of coil.

Abstract

Influenceof Bi2O3additiononthemicrostructureandmagneticpropertiesofLi-Cu-Mg-Znferriteshavingthe compositionsLi0.25Cu0.10Mg0.10Zn0.30Fe2.25O4+xBi2O3(wherex =0.0,0.3,0.4,0.6and0.8wt%)havebeen reportedinthisstudy.ThestructuralpropertyhasbeenstudiedwiththeX-raydiffractiontechnique,which reveals thatall thesampleshaveshownthecubicspinelphasewithoutanyimpuritypeak.Amicrostructural analysisdemonstrates that thegraingrowthof the samples is influencedby theamount of Bi2O3 addition resultinganincreaseoftheaveragegrainsizefrom0.84(forx=0.0wt%)to2.47µm(forx =0.6wt%).The developmentofthegrainsizecouldbeattributedtothedensificationofsampleduetotheformationoftheliquid phase of Bi2O3 in the sintering process. Themagnetic hysteresismeasurement shows that the saturation magnetizationincreases from72.1(forx=0.0wt%) to77.6emu/g(forx =0.6wt%Bi2O3).However, it declinedatx =0.8wt%,whichmaybeascribedtothedilutioneffect.Thecomplexmagneticpermeability measurement shows thatanenhancementof the initialpermeabilityisclearlyobservedwiththeadditionof Bi2O3 content. It is inferred that acorrelationhasbeen foundbetweenthegraingrowthandthemagnetic propertiesof theinvestigatedsamples.Fouriertransforms infraredabsorptionrevealsthat thefrequencyband appearsinthehighfrequency(539–555cm1)rangewhichcanbeattributedtothestretchingvibrationsatthe tetrahedralsite.Thebandappearinginthelowfrequency(359–373cm1)rangeisfortheoctahedralsite,which isduetobendingvibration.Theelasticconstants suchasbulkmodulus,Young’smodulus, rigiditymodulus, Poisson’sratioandPugh’sratiohavebeencalculatedforall thestudiedsamples. Itshowsthatallsynthesized samplesareinductilenature.

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