The trapping of Gd3+ excitation energy by Cr3+ and rare earth ions in GdAlO3

Abstract

The trapping of Gd3+ excitation energy by several activator ions in GdAlO3 is reported. The activator ions are Cr3+, Sm3+, Eu3+, Tb3+, Dy3+ Er3+ and Tm3+. If a broad, allowed absorption band of the activator overlaps with the 6I or 6P levels of Gd3+, efficient trapping is possible via multipolar interaction (trapping rate 106±s−1). Exchange interaction is responsible for trapping by rare-earth ions without such allowed absorption bands (trapping rate 103±s−1). At very low temperatures Gd3+ traps can act as efficient trapping centres, resulting in Gd3+ trap emission. The emission of Fe3+ on octahedral sites is also reported.