Electron paramagnetic resonance study of gadolinium in Czochralski-grown yttrium fluoride single crystals

Abstract

Single crystals of YF₃ grown by the Czochralski method have been investigated by electron paramagnetic resonance (EPR). In this paper we present an EPR analysis of residual Gd³⁺ impurities. We found that the Gd³⁺ rare-earth ion substitutes for Y³⁺ in YF₃. Detailed analysis of the EPR spectra allowed us to determine the fine structure parameters of Gd³⁺ in monoclinic C_s site symmetry. The EPR angular dependence is dominated by the electronic quadrupole tensor; the g-factor is slightly axial. The b⁰₂ parameter found for Gd³⁺ in YF₃ is unexpectedly high when compared to Gd³⁺ in the hosts of LaF₃ structure where the coordination number is the same. The results let us conclude that YF₃ is a promising laser host crystal.