Metal-insulator type transition in aluminium and chromium co-substituted nickel ferrites
1999; Elsevier BV; Volume: 39; Issue: 2 Linguagem: Inglês
10.1016/s0167-577x(98)00222-5
ISSN1873-4979
AutoresUrvi V. Chhaya, R.G. Kulkarni,
Tópico(s)Magnetic and transport properties of perovskites and related materials
ResumoPolycrystalline Al and Cr co-substituted disordered spinel series NiAlxCrxFe2−2xO4 with varying Al–Cr content (0.1≤x≤0.9) have been prepared in the pellet form and studied by X-ray diffraction, magnetization and electrical resistivity measurements. The lattice constants are determined and the applicability of Vegard's law has been tested. Samples with x≥0.5 exhibit a relatively sharp cusp in the electrical resistivity vs. temperature curve at T=Tmax identified as metal-insulator transition showing metallic behaviour for T Tmax. Metallic conductivity and ferrimagnetism occur in these x=0.5 to 0.9 samples mainly due to Cr spins and 3d transition metal electron correlation.
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