Structural, electronic, magnetic and calorimetric study of the metal-insulator transition in NdNiO3- delta

NdNiO 3 has been prepared using a low-temperature low-oxygen-pressure method. This compound has the same crystallographic structure as its homologous NdNiO 3 synthesized at high oxygen pressures. The sample obtained shows a metal-insulator transition at around 205 K with a large thermal hysteresis. The metallic phase shows a linear resistivity temperature dependence while, at low temperatures, conduction by variable-range hopping is observed. The heat capacity, magnetic susceptibility and electrical resistivity indicate carrier spin correlation even in the high-temperature metallic phase.