Local structure analysis of Mn^<2+> ions in γ-AlON by electron spin resonance

Abstract

In order to investigate the local structure of Mn^<2+> ions in bright oxynitride phosphors γ-AlON:Mn,Mg, electron spin resonance (ESR) measurements have been carried out at room temperature. The ESR spectra consist of six prominent peaks and five weak doublet structures. The former and latter correspond to allowed- and forbidden-transitions, respectively. The ESR spectrum measured is in good agreement with those due to Mn^<2+> ions in MgAl_2O_4 spinet, suggesting that Mn^<2+> ions are coordinated by four oxygen ions. An appearance of the doublet structures reveals that there is additional distortion around Mn^<2+> ions, resulting from the existence of two kinds of anions, namely, oxygen and nitrogen, and aluminum vacancies.