Space charge relaxation and clustering in yttrium doped BaF 2

Abstract

Characteristics of high temperature ionic thermocurrent (HT ITC) in BaF 2: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) = τ 00 T exp ( E a / kT). With the aid of a usual ITC method, a relation between the temperature of maximum ITC ( T m ) and yttrium concentration ( n) could be expressed in a form of T m = T mo −αn 1 3 . Furthermore, the activation energy ( E a ) follows E a ( n) = E ao − γn 1 3 and was explained by the Lidiard-Debye-Hückel (LDH) model.