Defect-property correlations in garnet crystals. VI. The electrical conductivity, defect structure, and optical properties of luminescent calcium and cerium-doped yttrium aluminum garnet

Abstract

The electrical and optical properties of calcium and cerium-doped yttrium aluminum garnet (Ca,Ce:YAG) have been studied. Ca,Ce:YAG is a mixed ionic and electronic conductor with an ionic conductivity activation energy of 4.3 eV. Evidence of cluster formation with a consequent higher-than-expected activation energy is presented. The cerium normally enters the crystal as Ce+4, but it may be converted to Ce+3 under reducing atmospheres at elevated temperatures.