The effect of Sr doping on the magnetic properties of Co perovskite

Abstract

Within the unrestricted Hartree–Fock approximation and the real space recursion method, we calculated the electronic structure of the La 1−xSr xCoO 3 in whole doping range 0.0≤ x≤1.0. The low-spin (LS, t 2 g 6 e g 0), the intermediate-spin (IS, t 2 g 5 e g 1), and the high-spin (HS, t 2 g 4 e g 2) states as well as their combinations in the doubled cell were taken as the initial configurations. It is found that the system is a nonmagnetic low-spin state ( t 2 g 6− x e g 0) for x≤0.25 and a ferromagnetic intermediate-spin state ( t 2 g 5 e g 1− x ) for 0.25< x≤0.41. For 0.41< x<0.95, the ground state of the system is a IS–HS ( t 2 g 5 e g 1− x - t 2 g 4 e g 2− x ) nearest neighbor ferromagnetically ordered state, which is followed by the HS state up to x=1.0. The ground state properties as a function of Sr doping are in accord with the experimental observations.