Linear colossal magnetoresistance driven by magnetic textures in LaTiO3 thin films on SrTiO3

TL;DR

This paper reports a colossal linear magnetoresistance in LaTiO3/SrTiO3 heterostructures driven by magnetic textures, achieving up to 6500% at 9T, revealing a new route for large-LMR device engineering.

Contribution

It demonstrates that magnetic textures, rather than structural disorder, can induce large linear magnetoresistance in oxide heterostructures, with detailed microscopic insights.

Findings

LMR reaches up to 6500% at 9T

Magnetic textures correlate with low-mobility regions

High film mobility up to 40,000 cm^2/V.s

Abstract

Linear magnetoresistance (LMR) is of particular interest for memory, electronics, and sensing applications, especially when it does not saturate over a wide range of magnetic fields. One of its principal origins is local mobility or density inhomogeneities, often structural, which in the Parish-Littlewood theory leads to an unsaturating LMR proportional to mobility. Structural disorder, however, also tends to limit the mobility and hence the overall LMR amplitude. An alternative route to achieve large LMR is via non-structural inhomogeneities which do not affect the zero field mobility, like magnetic domains. Here, linear positive magnetoresistance caused by magnetic texture is reported in \ch{LaTiO3}/\ch{SrTiO3} heterostructures. The LMR amplitude reaches up to 6500\% at 9T. This colossal value is understood by the unusual combination of a very high thin film mobility, up to 40 000 cm$^2$/V.s, and a very large coverage of low-mobility regions. These regions correlate with a striped magnetic structure, compatible with a spiral magnetic texture in the \ch{LaTiO3} film, revealed by low temperature Lorentz transmission electron microscopy. These results provide a novel route for the engineering of large-LMR devices.