Spin structures and band gap reduction of high-pressure triple perovskite Mn3MnTa2O9

Abstract

Herein we report the second transition-metal-only triple perovskite Mn₃MnTa₂O₉, from high pressure-high temperature transformation of Mn₄Ta₂O₉. It shows 1 : 2 Mn : Ta B-site order and a complex antiferromagnetic behavior with a collinear structure that modulates into a spin density wave. The high pressure phase presents a 25% band gap reduction compared to its multiferroic precursor, recoverable above 625 °C.