Variable Magnetism of Layer-Structured Compounds Cu2(OD)3X with Exchangeable Anion X: Magnetic Local Structure and Magnetic Interactions Determined by Solid-State High-Resolution Deuterium NMR

Abstract

The microscopic magnetic local structure of Botallackite-type layer-structured compounds Cu2(OD)3X (X = C6H5COO−) exhibiting a nonequilateral planar triangular copper lattice was determined by the solid-state high-resolution deuterium NMR above 190 K. The magnetic interaction in a copper layer was probed by the isotropic NMR shifts of OD− groups and could be approximated by a sum of 1D-Heisenberg chains in the high temperature region. Two copper chains with different exchange interactions J = −54 ± 4 and −92 ± 3 K were found for Cu2(OD)3C6H5COO from the temperature dependence of the three distinct NMR signals. The derived values of J almost reproduced the high temperature behavior of the magnetic susceptibility χA T vs. T. The magnetic susceptibility of isotopic analogue Cu2(OH)3C6D5COO showed ferromagnetic interaction below 50 K. Electron spin distribution in a phenyl ring of a benzoate anion is governed by spin polarization mechanism and it's magnitude is very small. Magnetic interaction between the layers through the benzoate anion is very weak.