EPR Investigation of KH₃(SeO₃)₂ Doped with Cr³⁺ Ions

Abstract

The EPR spectrum anisotropy of Cr 3+ in KH 3 (SeO 3 ) 2 single crystal is studied from 77 to 300 K. Two kinds of paramagnetic centres A and B are observed with (at room temperature) the spin Hamiltonian parameters: g x A =1.984, g y A =1.985, g z A =1.978, D A =0.218 cm -1 , E A =0.037 cm -1 ; g x B =1.967, g y B =1.966, g z B =1.968, D B =0.141 cm -1 , E B =0.024 cm -1 . Below the phase transition, each of the EPR lines of complexes A and B is split into two lines, differing in spin Hamiltonian parameter values. The crystal field parameter D is shown to be a sensitive indicator of the local spontaneous deformation in a ferroelastic.