Metal-insulator type transition in aluminium and chromium co-substituted nickel ferrites

摘要: Abstract Polycrystalline Al and Cr co-substituted disordered spinel series NiAl x Fe 2−2 O 4 with varying Al–Cr content (0.1≤ ≤0.9) have been prepared in the pellet form studied by X-ray diffraction, magnetization electrical resistivity measurements. The lattice constants are determined applicability of Vegard's law has tested. Samples ≥0.5 exhibit a relatively sharp cusp vs. temperature curve at T = max identified as metal-insulator transition showing metallic behaviour for insulating > . Metallic conductivity ferrimagnetism occur these =0.5 to 0.9 samples mainly due spins 3d metal electron correlation.