Intrinsic emission in quadratic-layer antiferromagnets: K2MnF4and Rb2MnCl4

Abstract
Emission from the first excited state of Mn2+ in antiferromagnetically ordered K2MnF4 and Rb2MnCl4 is reported. The emission from intrinsic exciton and exciton-magnon states has been identified. Lifetimes of the emission lines are measured and compared with those observed in KMnF3. The results suggest that the trapping of excitons at impurity centres is less probable in these systems compared with that in KMnF3.