Hysteretic Magnetoresistance in a Non-Magnetic SrSnO3 Film via Thermal Coupling to Dynamic Substrate Behavior

TL;DR

This study reveals that hysteretic magnetoresistance observed in a non-magnetic SrSnO3 film is caused by thermal effects from the substrate, not intrinsic magnetic properties, emphasizing the need to consider substrate influences in magnetotransport measurements.

Contribution

It demonstrates that substrate thermal coupling can induce hysteretic MR in non-magnetic oxide films, challenging the assumption that hysteresis indicates ferromagnetism.

Findings

Hysteresis in MR is due to substrate magnetocaloric effects, not film magnetism.

MR exceeds 100% at 1.8 K with in-plane field.

Thermal effects from GdScO3 substrate significantly influence magnetotransport data.

Abstract

Hysteretic magnetoresistance (MR) is often used as a signature of ferromagnetism in conducting oxide thin films and heterostructures. Here, magnetotransport is investigated in a non-magnetic uniformly La-doped SrSnO3 film grown using hybrid molecular beam epitaxy. A 12 nm La:SrSnO3/2 nm SrSnO3/GdScO3 (110) film with insulating behavior exhibited a robust hysteresis loop in the MR at T < 5 K accompanied by an anomaly at ~ +/- 3 T at T < 2.5 K. Furthermore, MR with the field in-plane yielded a value exceeded 100% at 1.8 K. Using detailed temperature-, angle- and magnetic field-dependent resistance measurements, we illustrate the origin of hysteresis is not due to magnetism in the film but rather is associated with the magnetocaloric effect of the GdScO3 substrate. Given GdScO3 and similar substrates are commonly used in complex oxide research, this work highlights the importance of thermal coupling to processes in the substrates which must be carefully accounted for in the data interpretation for thin films and heterostructures utilizing these substrates.