Charge transport and magnetization profile at the interface between a correlated metal and an antiferromagnetic insulator

TL;DR

This study investigates the charge transport and magnetic properties at the interface of CaRuO₃ and CaMnO₃ superlattices, revealing unexpected ferromagnetic polarization penetration possibly due to magnetic polarons.

Contribution

It provides detailed experimental insights into interfacial charge and magnetic behaviors, highlighting discrepancies with theoretical predictions and suggesting new magnetic phenomena.

Findings

Charge carrier density similar to bulk CaRuO₃

Small charge transfer across interface confirmed by density functional calculations

Ferromagnetic polarization penetrates 3-4 unit cells into CaMnO₃, exceeding predictions

Abstract

A combination of spectroscopic probes was used to develop a detailed experimental description of the transport and magnetic properties of superlattices composed of the paramagnetic metal CaRuO$_3$ and the antiferromagnetic insulator CaMnO$_3$. The charge carrier density and Ru valence state in the superlattices are not significantly different from those of bulk CaRuO$_3$. The small charge transfer across the interface implied by these observations confirms predictions derived from density functional calculations. However, a ferromagnetic polarization due to canted Mn spins penetrates 3-4 unit cells into CaMnO$_3$, far exceeding the corresponding predictions. The discrepancy may indicate the formation of magnetic polarons at the interface.