Crystals of Eu3+-doped material were tested in a diamond-anvil cell, at high pressures and temperatures, in order to produce a non-equilibrium distribution of charge-compensating interstitial fluorides. The re-equilibration dynamics were then studied by annealing the treated sample at normal pressures. The re-equilibration covered a temperature range of 80, and corresponded to an 0.34eV range in the diffusional activation energy.

Localized Fluoride Diffusion and Defect Equilibrium in CaF2:Eu3+ using Site-Selective Spectroscopy and High-Pressure Techniques. L.R.Olsen, A.O.Wright, J.C.Wright: Physical Review B, 1996, 53[21], 14135-44