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

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-5, site symmetry. The EPR angular dependence is dominated by the electronic quadrupole tensor; the g-factor is slightly axial. The b(2)(0) 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.