Spontaneous cationic ordering in chemical-solution-grown La2CoMnO6 double perovskite thin films

Hailin Wang,Carlos Frontera,Matthew F Chisholm,Benjamin Martinez,Narcis Mestres,Jaume Gazquez,Alberto Pomar

doi:10.1038/s41427-019-0144-8

Abstract

Double perovskite oxides are of interest because of their electric, magnetic, and elastic properties; however, these properties are strongly dependent on the ordered arrangement of cations in the double perovskite structure. Therefore, many efforts have been made to improve the level of cationic ordering to obtain optimal properties while suppressing antisite defect formation. Here, epitaxial double perovskite La2CoMnO6 thin films were grown on top of (001)-STO oriented substrates by a polymer-assisted deposition chemical solution approach. Confirmation of the achievement of full Co/Mn cationic ordering was found by scanning transmission electron microscopy (STEM) measurements; EELS maps indicated the ordered occupancy of B–B′ sites by Co/Mn cations. As a result, optimal magnetic properties (Msat ≈ 6 µB/f.u. and Tc ≈ 230 K) are obtained. We show that the slow growth rates that occur close to thermodynamic equilibrium conditions in chemical solution methods represent an advantageous alternative to physical deposition methods for the preparation of oxide thin films in which complex cationic ordering is involved.

Highlights

Complex oxides are a class of materials with a plethora of physical properties of strong interest for many different technological applications from catalysis to spintronics[1,2]
High-quality epitaxial LCMO films have been prepared with a single one-step growth process using the Polymer-assisted deposition (PAD) technique on top of STO (001)-oriented substrates
Further support for the existence of full Co/Mn cationic ordering is obtained by scanning transmission electron microscopy (STEM) measurements; energy loss spectroscopy (EELS) maps indicate the ordered occupancy of B–B′ sites by Co/Mn cations

Summary

Introduction

Complex oxides are a class of materials with a plethora of physical properties of strong interest for many different technological applications from catalysis to spintronics[1,2]. The growth of LCMO on (111)-SrTiO3 (STO) substrates has been explored using metal–organic aerosol deposition (MAD)[25], and excellent saturation magnetization (Msat) and Curie temperature values indicative of high cationic ordering have been obtained.

Results

Conclusion