Aqueous Chemical Solution Deposition of Functional Double Perovskite Epitaxial Thin Films

Double perovskite structure (A2BB′O6) oxides exhibit a breadth of multifunctional properties with a huge potential range of applications in fields as diverse as spintronics, magneto‐optic devices, or catalysis, and most of these applications require the use of thin films and heterostructures. Chemical solution deposition techniques are appearing as a very promising methodology to achieve epitaxial oxide thin films combining high performance with high throughput and low cost. In addition, the physical properties of these materials are strongly dependent on the ordered arrangement of cations in the double perovskite structure. Thus, promoting spontaneous cationic ordering has become a relevant issue. In this work, our recent achievements by using polymer‐assisted deposition (PAD) of environmentally friendly, water‐based solutions for the growth of epitaxial ferromagnetic insulating double perovskite La2CoMnO6 and La2NiMnO6 thin films on SrTiO3 and LaAlO3 single‐crystal substrates are presented. It is shown that the particular crystallization and growth process conditions of PAD (very slow rate, close to thermodynamic equilibrium conditions) promote high crystallinity and quality of the films, as well as favors spontaneous B‐site cationic ordering.We acknowledge financial support from the Spanish Ministry of Science, Innovation and Universities through Severo Ochoa (SEV‐2015–04969), SUMATE (RTI2018‐095853‐B‐C21), and SPINCURIOX (RTI2018‐099960‐B‐I00) projects co‐financed by the European Regional Development Fund. Hailin Wang acknowledges financial support from the China Scholarship Council (CSC). This work has been performed in the framework of the Ph.D. program in Materials Science of the Universitat Autònoma de Barcelona (UAB), through the CSC/UAB Joint Scholarship. The authors thank the ALBA Synchrotron (Spain) for the provision of beamtime. The authors also thank Dr. B. Bozzo and F. J. Campos for their technical support during magnetic and X‐ray diffraction measurements.Peer reviewe