Engineering of Ferroic Orders in Thin Films by Anionic Substitution

TL;DR

This paper reports the discovery of room-temperature multiferroic orders in SrNbO3-xNx thin films, achieved through multi-anion engineering, revealing new pathways for designing multiferroic materials with strong magnetoelectric coupling.

Contribution

It introduces a novel multiferroism design strategy by engineering multi-anion states in thin films, expanding the range of multiferroic materials with strong room-temperature properties.

Findings

Room-temperature ferromagnetic ordering in SrNbO3-xNx thin films.

Ferroelectric responses linked to structural symmetry breaking.

Multi-anion engineering as a new design approach for multiferroics.

Abstract

Multiferroics are a unique class of materials where magnetic and ferroelectric orders coexist. The research on multiferroics contributes significantly to the fundamental understanding of the strong correlations between different material degrees of freedom and provides an energy-efficient route toward the electrical control of magnetism. While multiple ABO3 oxide perovskites have been identified as being multiferroic, their magnetoelectric coupling strength is often weak, necessitating the material search in different compounds. Here, we report the observation of room-temperature multiferroic orders in multi-anion SrNbO3-xNx thin films. In these samples, the multi-anion state enables the room-temperature ferromagnetic ordering of the Nb d-electrons. Simultaneously, we find ferroelectric responses that originate from the structural symmetry breaking associated with both the off-center displacements of Nb and the geometric displacements of Sr, depending on the relative O-N arrangements within the Nb-centered octahedra. Our findings not only diversify the available multiferroic material pool but also demonstrate a new multiferroism design strategy via multi-anion engineering.