Characterization of Czochralski-grown orthorhombic β-LuF3:Ce by electron paramagnetic resonance

Cerium doped fluoride materials are known for their fast scintillating properties. Large LuF3 single crystals have been grown by the Czochralski method. Electron paramagnetic resonance (EPR) has been used to characterize Ce3+ and residual paramagnetic impurities. At 300 K Gd3+ has been detected, which substitutes for Lu3+ in LuF3. From the analysis of the EPR angular dependence the b 2 0 parameter for Gd3+ was determined to be 1.846 GHz, which is about times larger than the corresponding parameter in LaF3 hosts structure. At 10 K the EPR spectra show the presence of Ce3+ and other still undetermined rare earth impurities. The analysis of the EPR angular dependence of Ce3+ shows a strong nearly axial symmetry of the g tensor with g xx = 0.29, g yy = 0.60 and gzz = 3.374. The Y axis of the g tensor is parallel to the crystallographic b direction, whereas the X and Z axes are rotated in the ac plane by 25°.