Magnetism of the A-site ordered perovskites CaCu3Cr4 O12 and LaCu3Cr4 O12

Abstract

The microscopic magnetic nature of the A-site ordered chromium perovskites CaCu3Cr4O12 and LaCu3Cr4O12 and their solid-solution system, Ca1-xLaxCu3Cr4O12, with x=0.2, 0.4, and 0.8, has been studied with muon spin rotation and relaxation (μ+SR) measurements down to 2 K using a powder sample. For CaCu3Cr4O12, μ+SR revealed the formation of static antiferromagnetic (AF) order below 122 K (=TN), although magnetization measurements showed a very small change at TN. Analyses of the internal magnetic field Hint at the muon sites, predicted with first-principles calculations, suggested G-Type AF order as a ground state. For LaCu3Cr4O12 with TN=225 K, μ+SR also supported the presence of a G-Type AF ordered state, which was recently proposed based on neutron diffraction measurements. However, the ordered Cr moments were found to change the direction at around 10 K. For Ca1-xLaxCu3Cr4O12, both TN and Hint at 2 K increase monotonically with x.