Giant topological Hall effect in correlated oxide thin films

TL;DR

This paper reports a giant topological Hall effect in correlated oxide thin films, linked to magnetic textures resembling skyrmions, with effects strongly amplified by electronic correlations and tunable by carrier concentration.

Contribution

It demonstrates a large topological Hall effect in correlated oxide thin films and explores its dependence on correlations and carrier doping, revealing potential for electric field control.

Findings

Giant topological Hall effect observed in (Ca, Ce)MnO3 thin films.

Magnetic bubbles correlate with Hall effect peaks, resembling skyrmions.

Hall effect diverges near the metal-insulator transition at low doping.

Abstract

Strong electronic correlations can produce remarkable phenomena such as metal-insulator transitions and greatly enhance superconductivity, thermoelectricity, or optical non-linearity. In correlated systems, spatially varying charge textures also amplify magnetoelectric effects or electroresistance in mesostructures. However, how spatially varying spin textures may influence electron transport in the presence of correlations remains unclear. Here we demonstrate a very large topological Hall effect (THE) in thin films of a lightly electron-doped charge-transfer insulator, (Ca, Ce)MnO3. Magnetic force microscopy reveals the presence of magnetic bubbles, whose density vs. magnetic field peaks near the THE maximum, as is expected to occur in skyrmion systems. The THE critically depends on carrier concentration and diverges at low doping, near the metal-insulator transition. We discuss the strong amplification of the THE by correlation effects and give perspectives for its non-volatile control by electric fields.