Enhanced susceptibility in LNiO3 perovskites (L = La, Pr, Nd, Nd0.5Sm0.5)

The temperature dependence of the resistivity rho(T) and of the de magnetic susceptibility chi(T) were measured on high-quality LNiO3 (L = La, Pr, Nd, Nd0.5Sm0.5) samples synthesized under high oxygen pressure. Subtraction of ;he rare-earth contribution to chi(T) allows the presentation of the evolut ion of the susceptibility of the NiO3 array from Pauli to Curie-Weiss param agnetism with decreasing bandwidth. A metal-insulator transition occurring at a temperature T-t =T-N is first order for L = Pr and Nd; it becomes seco nd order and produces no anomaly in chi(-1)(T) at a T-t > T-N for L = Nd0.5 Sm0.5. In the antiferromagnetic domain T < T-N, the chi(T) curve for the Ni O3 array resembles that of a paramagnet. PACS numbers: 71.28. + d, 71.30. h, 75.20.-g.