Ferromagnetic insulating epitaxially strained La2NiMnO6 thin films grown by sputter deposition

G De Luca,M D Rossell,J Spring,C Dominguez,C Piamonteze,M Döbeli,T Greber,U Bashir,R Totani,M Campanini,M Gibert,A Zakharova

doi:10.1063/5.0055614

Abstract

The field of oxide spintronics can strongly benefit from the establishment of ferromagnetic insulators with near room-temperature Curie temperature. Here, we investigate the structural, electronic, and magnetic properties of epitaxially strained thin films of the double perovskite La2NiMnO6 (LNMO) grown by off-axis radio-frequency magnetron sputtering. We find that the films retain insulating behavior and a bulk-like Curie temperature in the order of 280 K independently of the 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.

Highlights

The development of robust and easy to integrate ferromagnetic insulators (FMIs) is a crucial objective for the progress of next-generation dissipationless oxide spintronic devices.[1,2,3] the coexistence of these features is rarely found in nature, mainly because the electrons that mediate FM interactions are typically itinerant.[4]
We have shown that off-axis radio-frequency scitation.org/journal/apm (RF) magnetron sputtering is a suitable growth method to produce atomically precise, stoichiometric, and cation-ordered LNMO thin films
We find that our films are characterized by an insulating behavior paired with a TC in the order of 280 K, independent of epitaxial strain

Summary

INTRODUCTION

The development of robust and easy to integrate ferromagnetic insulators (FMIs) is a crucial objective for the progress of next-generation dissipationless oxide spintronic devices.[1,2,3] the coexistence of these features is rarely found in nature, mainly because the electrons that mediate FM interactions are typically itinerant.[4] Transition metal oxides, and in particular perovskite-based systems, have been widely studied in the last few decades because of the vast combination of functionalities that can be hosted in a relatively simple structure.[5,6] Recent efforts, have demonstrated that doping, off-stoichiometry, epitaxial strain, and interface engineering are examples of feasible strategies to obtain a FMI behavior in perovskite oxide heterostructures.[7,8,9,10,11] These exotic states are, in competition with a metallic one, suggesting that their adoption in a device architecture could be fragile. These results suggest that the magnetic interaction between Ni and Mn in the LNMO system is pretty robust against structural changes and suitable for a variety of spintronic devices where a high-temperature FM insulating state is essential

STRUCTURAL AND ELECTRONIC PROPERTIES

MAGNETIC PROPERTIES

SUMMARY AND CONCLUSIONS