XRD and Mössbauer studies of crystallographic and magnetic transformations in synthesized Zn-substituted Cu–Ga–Fe compound

Abstract

System of samples in the form of Cu 1− x Zn x Fe 2− y Ga y O 4 with ( 0.0 ⩽ x ⩽ 1.0 , y = 0.0 and 1.0) is synthesized. X-ray diffraction study confirms the presence of a single-phase structure, where tetragonal unit cell is obtained for samples CuFe 2O 4 and CuGaFeO 4 with c / a > 1 . At compositional parameter x ⩾ 0.25 , tetragonal-to-cubic transformation occurs. The determined lattice parameter a for the cubic samples is found to decrease with increasing Zn content x. 57Fe Mössbauer measurements at 293, 77 and 12 K show characteristic spectra of paramagnetic, magnetic, and electronic types for the different compositions. Cation distribution obtained from the spectral analysis at 12 K revealed transformation from the ferrimagnetic inverse spinel of CuFe 2O 4 to the antiferromagnetic normal spinel of ZnFe 2O 4. Hyperfine parameters are found to be strongly dependent on temperature and concentration parameter x. Low-temperature measurements are carried out using installed and well-calibrated closed-cycle variable temperature cryostat Model REF-399-D22. Low vibration is obtained through bellows, spacer, and exchange gas isolation and a difference of 0.018 mm s −1 between the FWHM of a pure iron foil at room temperature and 12 K is achieved.