Multifrequency EPR study of Cr3+ ions in LiScGeO4

Abstract

An electron paramagnetic resonance study of a synthetic single crystal of Cr-doped LiScGeO4 was carried out at the X-and Q-bands at 300 K and at the broad band (70-370 GHz) at 4.2 K. It was established that the EPR spectra with the magnetic multiplicity KM = 2 observed in all the frequency bands are due to the Cr3+ substituted for Sc3+ at the mirror symmetry octahedral site. The angular dependences of the two symmetry-related spectra of Cr3+ in the three crystallographic planes were fitted with the spin Hamiltonian (S = 3/2) of monoclinic symmetry. The zero-field splitting of the ground state energy levels was determined as 1.309(5) cm-1 which compares well with that for Cr3+ in forsterite and alexandrite crystals with similar olivine-like structure. Additional weak lines due to Mn2+ and Fe3+ at the mirror symmetry sites were also identified in the X- and Q-band spectra.