Anomalous excitation profile and its relationship to multiple dopant sites in (Nd, Cr) YAlO3

Abstract

Excitation spectra of (Nd 3+ , Cr 3+ )YAlO 3 are presented which show anomalous profiles. We demonstrate that these anomalous lineshapes can be explained by a combination of three physical mechanisms: the existence of several inequivalent Nd sites, the existence of significant energy transfer from Cr 3+ to Nd 2+ and strong absorption of the excitation beam by Nd 3+ ions. Reasons for residual asymmetry in excitation profiles are discussed with particular emphasis on a Fano effect