# Topological Hall Effect and Emergent Skyrmion Crystal in Manganite-Iridate Oxide Interfaces

## TL;DR

This study demonstrates the emergence of a skyrmion crystal phase and the associated topological Hall effect at manganite-iridate interfaces, revealing new magnetic and transport phenomena in oxide heterostructures.

## Contribution

It introduces a theoretical model showing the formation of skyrmion crystals driven by Dzyaloshinskii-Moriya interactions at manganite-iridate interfaces, linking magnetic textures to Hall effects.

## Key findings

- Identification of a skyrmion-crystal phase at low temperatures.
- Observation of a topological Hall effect in the skyrmion phase.
- Discovery of a skyrmion-gas phase at higher temperatures.

## Abstract

Scalar spin chirality is expected to induce a finite contribution to the Hall response at low temperatures. We study this spin-chirality-driven Hall effect, known as the topological Hall effect, at the manganite side of the interface between La$_{1-x}$Sr$_{x}$MnO$_{3}$ and SrIrO$_3$. The ferromagnetic double-exchange hopping at the manganite layer, in conjunction with the Dzyaloshinskii-Moriya (DM) interaction which arises at the interface due to broken inversion symmetry and strong spin-orbit coupling from the iridate layer, could produce a skyrmion-crystal (SkX) phase in the presence of an external magnetic field. Using the Monte Carlo technique and a two-orbital spin-fermion model for manganites, supplemented by an in-plane DM interaction, we obtain phase diagrams which reveal at low temperatures a clear SkX phase and also a low-field spin-spiral phase. Increasing temperature, a skyrmion-gas phase, precursor of the SkX phase upon cooling, was identified. The topological Hall effect primarily appears in the SkX phase, as observed before in oxide heterostructures. We conclude that the manganite-iridate superlattices provide another useful platform to explore a plethora of unconventional magnetic and transport properties.