Anomalies in the cathodoluminescence of the antiferromagnetic oxides NiO and CoO

Abstract

Cathodoluminescence (CL) of the antiferromagnetic oxides NiO and CoO has been investigated. Both compounds show luminescence bands in the visible and near infrared spectral ranges, tentatively attributed to intra-ionic transitions. Dependence of the visible CL intensity with temperature presents anomalies at about half of the Neel temperature, which are explained by the existence of magnetic ordering effects. The results are briefly compared with previous reports on the CL from YBa_2Cu-3O-(7-x).