Cation distribution and magnetic properties of nickel-chromium ferrites NiCr_xFe_2-xO₄ (0 ≤ x ≤ 1.4)

Nickel-chromium ferrites NiCr_xFe_2-xO₄ (0 ≤ x ≤ 1.4) were studied using X-ray diffraction, magnetization measurements and Mössbauer spectroscopy. X-ray diffraction patterns show that all samples have cubic spinel structure. The temperature dependent magnetic measurements revealed that a magnetic compensation point appears at chromium concentration x = 0.9, 1.2 and 1.4. Moreover, it was observed that the Curie temperature T_C decreases and approaches the compensation temperature T_K as Cr³⁺ substitution for Fe³⁺ increases. The magnetization data at all concentrations are discussed in the light of Néel's molecular field model taking into account the cation distributions obtained using the analysis of Mössbauer spectra.