Exchange Interactions in Heteronuclear Clusters Containing Dysprosium Ions: EPR Spectroscopy Possibility

Abstract

The exchange interaction in two isostructural compounds [M2Dy2 (μ3–OH)2(L)2(O2CPh–Me–p)6] (M = Al, Cr) is studied by electron paramagnetic resonance (EPR). Studies have been performed on polycrystalline samples in different frequency ranges. The features of the shape of the spectra of clusters containing dysprosium ions are analyzed and experimental spectra are described using calculated spectra for tetranuclear clusters. The value Jzz = − 0.86 cm−1 of the spin–spin interaction of the Ising form JzzS1zS2z between dysprosium ions in the Al2Dy2 cluster, which exhibits single-molecule magnet properties, was experimentally determined. The study of the heteronuclear Cr2Dy2 cluster has demonstrated a number of features of the EPR spectra due to the Cr–Dy interaction. It is shown that this interaction has a predominantly Ising form with the parameter JCrDyzz = − 1 cm−1. However, the Cr–Dy pair fragment does not have a center of symmetry, and this suggests the presence of an antisymmetric term in the spin–spin interaction tensor, the manifestation of which is observed in the X-band EPR spectrum.