ITC in non‐irradiated and in UV irradiated SrF₂:Tb crystals

Ionic thermocurrents (ITC) in Tb³⁺ doped SrF₂ crystals were investigated, especially in the temperature range 300 to 500 K. A strong complex charge‐displacement peak appeared at about 365 K. Its activation energy and frequency factor were found to be 1.03 eV and 2 × 10¹² s⁻¹. This peak was attributed to the motion of F⁻ interstitials. Some weaker peaks due to dipole reorientation appeared between 80 and 300 K. Irradiating the polarized crystal with non‐ionizing UV light caused the appearance of an additional current peak at about 278 K. This peak was accompanied by a thermoluminescence (TL) glow peak and both were ascribed to the thermal release of trapped holes from V‐type centers. It appears that some of the current peaks do not follow first order kinetics. An expression for ITC peaks of general order kinetics is discussed.