Neutron investigation of Ru-doped Nd_1/2Ca_1/2MnO₃–Comparison with Cr-doped Nd_1/2Ca_1/2MnO₃–

Abstract

Lattice and magnetic properties are investigated for 3% Ru- and Cr-doped Nd 1/2 Ca 1/2 MnO 3 . The parent Nd 1/2 Ca 1/2 MnO 3 is a charge-ordered insulator ( T CO = 250 K). With decreasing temperature below ≈ 210 K, these compounds are separated into two perovskite phases, that is, the long- c and short- c phases. The long- c region shows a ferromagnetic transition at T C ≈210 K for the Ru-doped compound and ≈ 130 K for the Cr-doped compound, while the short- c region shows antiferromagnetic transition at T N ≈150 K for Ru and ≈ 110 K for Cr. We discuss the origin of the enhanced T C for the Ru-doped compound in terms of the effective one-electron bandwidth W of the e g -band.