Anisotropic Exchange Interactions in Cuprates

Abstract

For the antiferromagnets of insulating cuprates which are parent compounds of high-T_c copper oxides, it is shown that an anisotropic “direct” exchange interaction (pseudo-dipolar interaction) is responsible for the easy-plane anisotropy which makes spins lie in CuO₂ planes. This argument is confirmed by showing that the same origin is responsible for the anisotropy in a related ferromagnetic compound, K₂CuF₄.