首页|(162836)Magnetic, structural and magnetocaloric effect investigations on the substituted spinel Mg_(1-x)Zn_xFe_2O_4 (0 ≤ x ≤1) prepared by sol-gel method
(162836)Magnetic, structural and magnetocaloric effect investigations on the substituted spinel Mg_(1-x)Zn_xFe_2O_4 (0 ≤ x ≤1) prepared by sol-gel method
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NSTL
Elsevier
Polycrystalline Mg_(1-x)Zn_xFe_2O_4 (0 ≤ x ≤1) ferrites were prepared with sol-gel method. The obtained samples were characterized by powder X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and Mossbauer spectrometry. The X-ray diffraction analysis combined with the Rietveld refinement confirmed that the samples crystallize in a single-phase cubic spinel structure with (SG: Fd3m) and an average grain size in the range of 29.1-40 nm. Lattice parameter increases with increasing Zn concentration, due to the larger ionic radius of Zn~(2+) ions in regard of Mg~(2+) ions. The Curie temperature T_c decreases linearly with substitution. Saturation magnetization (M_s), magnetic moment of iron (u_Fe)) and magnetic entropy change (-ΔS_M) increase for x≤ 0.5 and decrease for x≥ 0.5, this behavior is attributed to the cationic distribution of the ions on tet-rahedral [A] and octahedral [B] sites, where the structure turns from partially inverse spinel to normal spinel, affecting the remanent magnetization and the coercitive field. Moreover, a new empirical relation is acquired performing linear relation between magnetic moment and the inversion parameter 6. Mossbauer spectra show a transformation from sextuple to an only a doublet which indicates a transformation from ferrimag-netic to paramagnetic phase, this ferrimagnetism degradation is confirmed by the negative values of-ΔS_M and the transition of the magnetocaloric effect from normal to inverse through substitution.
NSTL
Elsevier
