O^– centers in LuAG:Ce,Mg ceramics

Abstract

Electron traps are known to a have great influence on the carriers transport process in Ce based scintillators. On the other hand, the role of hole traps in the scintillation process has been less considered. By means of electron spin resonance (ESR), we detected hole traps in highly Ce‐doped LuAG:Ce,Mg ceramics in the form of σ‐type O – centers. The g ‐tensor components turn out to be g ⊥ = 2.0103, and g || = 2.0023, revealing the axial symmetry of these defects. Mg‐perturbed variants of O – centers are proposed to exist in LuAG:Ce,Mg. Their occurrence is related to an elongated Mg–O bond as evidenced by DFT calculations. Finally, the multiple role of O – centers in the scintillation process is discussed. magnified image (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)