Evolution of magneto-orbital order upon B-site electron doping in Na1-xCaxMn7O12 quadruple perovskite manganites

TL;DR

This study uncovers a new incommensurate magnetic phase in Na1-xCaxMn7O12 quadruple perovskites, revealing how B-site electron doping influences magneto-orbital order through exchange interactions, unifying magnetic phenomena across related compounds.

Contribution

It introduces a new magnetic phase in quadruple perovskites and a simple mean field model explaining the interplay of charge, magnetic, and orbital orderings.

Findings

Discovery of an incommensurate magnetic phase in Na1-xCaxMn7O12

Demonstration of exchange interactions between A and B sites causing magnetic order

Unified description of charge, magnetic, and orbital interplay across compounds

Abstract

We present the discovery and refinement by neutron powder diffraction of a new magnetic phase in the Na1-xCaxMn7O12 quadruple perovskite phase diagram, which is the incommensurate analogue of the well-known pseudo-CE phase of the simple perovskite manganites. We demonstrate that incommensurate magnetic order arises in quadruple perovskites due to the exchange interactions between A and B sites. Furthermore, by constructing a simple mean field Heisenberg exchange model that generically describes both simple and quadruple perovskite systems, we show that this new magnetic phase unifies a picture of the interplay between charge, magnetic and orbital ordering across a wide range of compounds.