Investigations of the spin hamiltonian parameters and local structure for Cr3+ in K2PdCl4 single crystal

Abstract

The spin Hamiltonian parameters (SHPs) (g factors and zero-field splittings (ZFSs) D and E) and the local structure for Cr3+ in K2PdCl4 single crystal are theoretically investigated from the perturbation calculations of the SHPs for an orthorhombically distorted octahedral 3d3 cluster. The impurity Cr3+ is found not to occupy the conventional square planar Pd2+ site but to locate at the octahedral K+ site, associated with the relative axial compression ratio ρ(≈ 11.1%) and the perpendicular bond length variation ratio τ (≈ 11.7%). The impurity centre exhibits much smaller axial compression distortion and much larger perpendicular orthorhombic distortion than the host K+ site in K2PdCl4 (ρH ≈ 18.6% and τH ≈ 0) and hence a more regular ligand octahedron, corresponding to the very small ZFSs. The contributions to g-shifts ∆gCT from the CT mechanism are opposite in sign and twenty-one times larger in magnitude compared with ∆gCF from the CF mechanism. For the ZFSs, the CT contributions DCT and ECT are opposite in sign and almost the same in magnitude with respect to the corresponding DCF and ECF.