Robust ferromagnetism in insulating La$_2$NiMnO$_6$ thin films

TL;DR

This study demonstrates that La$_2$NiMnO$_6$ thin films maintain robust ferromagnetic insulating properties near room temperature regardless of epitaxial strain, making them promising for oxide spintronics applications.

Contribution

The paper reports the synthesis and characterization of epitaxially-strained La$_2$NiMnO$_6$ thin films that exhibit stable ferromagnetic insulating behavior at temperatures close to 280 K, independent of strain conditions.

Findings

Films are strongly insulating with bulk-like Curie temperature (~280 K).

Epitaxial strain does not significantly affect magnetic or electronic properties.

Potential for use in high-temperature ferromagnetic insulator-based devices.

Abstract

The field of oxide spintronics can strongly benefit from the establishment of robust ferromagnetic insulators with near room-temperature Curie temperature. Here we investigate the structural, electronic, and magnetic properties of atomically-precise epitaxially-strained thin films of the double perovskite La$_2$NiMnO$_6$ (LNMO) grown by off-axis radio-frequency magnetron sputtering. We find that the films retain both a strong insulating behavior and a bulk-like Curie temperature in the order of 280 K, nearly independently from epitaxial strain conditions. These results suggest a prospective implementation of LNMO films in multi-layer device architectures where a high-temperature ferromagnetic insulating state is a prerequisite.