The exchange interaction values of perovskite-type materials EuTiO_3 and EuZrO_3

摘要

A comprehensive research of the antiferromagnetic (AFM) structures of perovskite-type EuTiO_3 and EuZrO_3 is carried out by use of the double-time Green's function. All three possible types of AFM configurations are considered, and theoretical results are compared to experiments to extract the exchange parameters J_1 and J_2 values. The obtained exchanges are employed to calculate the magnetic susceptibility, which is then, in turn, compared to experiments. In this way, we can be certain that the EuZrO_3, as well as EuTiO_3, is of the G-type structure ever conjectured, and A- and C-types are ruled out. Our achieved J_1 and J_2 values are compared with those obtained by the mean field approximation and Monte Carlo simulation, and better agree with experiments.