Ferro- and antiferromagnetic interactions of layer-structured basic copper compounds as studied by solid-state high-resolution deuterium NMR

Abstract

Magnetic local structure of a ferromagnetic layer-structured basic copper compound Cu2(OD)1.96(C4H6(COO)2)1.02·0.07D2O with dicaboxylate anion was examined by solid-state high-resolution deuterium NMR above 200 K. The magnetic interaction in a copper layer was probed by the isotropic D NMR shift of OD− ions. Only one strong signal was observed for the OD− ions of Cu2(OD)1.96(C4H6(COO)2)1.02 0.07D2O, while more than two signals corresponding to different magnetic chains of Cu2+ ions in a layer were observed for most of Cu2(OD)3X where X was univalent anion. A ferromagnetic exchange interaction J=+71 K within a copper layer was estimated from the temperature dependence of the isotropic D NMR shift by assuming an one-dimensional Heisenberg model. A layer-structured compound Cu2(OH)3(SCN) with non-oxygen atom coordination for bridging copper ions was synthesized by anion exchange reaction. The magnetic susceptibility measurement indicates that a weak ferromagnetic interaction dominates in the high temperature region and a weak antiferromagnetic interaction appears in the low temperature region.