Emergence of a Magnetostructural Dipolar Glass in the Quadruple Perovskite Dy1−δMn7+δO12<

Abstract

We show that a polar, pseudo-Jahn-Teller instability exists for the underbonded rare-earth A-site cations in the quadruple perovskite Dy 1−δ Mn 7þδ O 12 , which leads to the spontaneous formation of a dipolar glass. This observation alone expands the applicability of pseudo-Jahn-Teller physics in perovskite-derived materials, for which it is typically confined to B-site cations. We demonstrate that the dipolar glass order parameter is coupled to a ferrimagnetic order parameter via strain, leading to a first order magnetostructural phase transition that can be tuned by magnetic field. This phenomenology may emerge in a broad range of perovskite-derived materials in which A-site cation ordering and octahedral tilting are mutually tied to meet the criteria of structural stability.

Robust Crystal Phase Separation with Distinct Charge, Orbital, and Spin Orders in AgMn7O12

“…To date, for the above-mentioned AMn 7 O 12 family, many kinds of members with bivalent (e.g., Ca 2+ , Cd 2+ , Sr 2+ , Hg 2+ , Pb 2+ , and Mn 2+ ) − and trivalent (e.g., rare earth R 3+ ions and Bi 3+ ) − A-site ions have been studied. However, the monovalent A-site ion is observed only in NaMn 7 O 12 .…”