Low temperature electrical transport in La1-xNdxNiO3-δ

We have investigated low temperature electrical transport in La1-xNdxNiO3-delta perovskite oxide samples. Samples were prepared by a sol-gel method and were characterized by X-ray diffraction and chemical methods. High precision electrical resistivity, magnetoresistance (MR) and electron tunneling conductance measurements were performed. Crystal structure investigations showed a phase transition from rhombohedral to orthorhombic phase at x = 0.4. In the orthorhombic phase Ni-O-Ni bond angle was found to depend very sensitively on the value Of V; as the value of x increases Ni-O-Ni bond angle decreases resulting in the tilting of NiO6 octahedra. A Correlation between the Ni-O-Ni bond angle and electrical transport has been observed. The analysis of the electrical resistivity data showed the presence of disorder driven quantum Correction effects, namely e-e interactions and weak localization, in the system. A dip in the tunneling density of states and negative MR also suggest the presence of e-e interaction and weak localization effects in the system. (C) 2002 Published by Elsevier Science Ltd.