Space charge relaxation and clustering in yttrium doped BaF2

Characteristics of high temperature ionic thermocurrent (HT ITC) in BaF2:Y were studied by varying yttrium concentration. A thermal sampling ITC (TS ITC) method was used to decompose the HT ITC band and revealed that the high temperature part of the band consists of a single and intense ITC one. The HT ITC spectra could be analyzed by a space charge flow model with a relaxation time of τ(T) = τ00Texp(Ea/kT). With the aid of a usual ITC method, a relation between the temperature of maximum ITC (Tm) and yttrium concentration (n) could be expressed in a form of Tm = Tmo−αn13. Furthermore, the activation energy (Ea) follows Ea(n) = Eao − γn13 and was explained by the Lidiard-Debye-Hückel (LDH) model.