Route to high Néel temperatures in 4d and 5d transition metal oxides

Abstract

There are very few magnetic members among the 4d and 5d transition metal oxides. In the present work, we examine the recent observation of a high Néel temperature T_N in the 4d oxides SrTcO₃ and CaTcO₃. Considering a multiband Hubbard model, we find that T_N is larger in the limit of a large bandwidth and vanishingly small intra-atomic exchange interaction strength, contrary to our conventional understanding of magnetism. This is traced to specific aspects of the d³ configuration at the transition metal site and the study reveals additional examples with high T_N.