Magnetism and magnetoresistance in Al half doped LaNiO3

Abstract

Abstract The rhombohedral perovskite LaAl0.5Ni0.5O3 (or La2AlNiO6), synthesized by a combustion method is found to contain Al3+ and Ni3+ cations in the rhombohedral lattice. The material exhibits a temperature dependent (thermally excited) paramagnetic susceptibility and follows the modified Curie-Weiss law implying an antiferromagnetic ordering at very low temperatures. A non-saturating hysteresis loop with a coercivity of 108\u202fOe is observed at 2\u202fK which is arising from the magnetic contribution from Ni in the lattice. The conduction mechanism in LaAl0.5Ni0.5O3 for 80–300\u202fK follows the Mott s variable range hopping mechanism. A negative magnetoresistance of 1.75% is observed at 2\u202fK under 90\u202fkOe field which decreases linearly by increasing the temperature up to 18\u202fK and then changes to positive with comparatively low value. Both the negative and positive magnetoresistance increases linearly with an applied magnetic field.