Realization of Monophased LaCoOx Films with Ordered Oxygen Vacancies

Compared to their parent materials, oxygen vacancy (V-O)-ordered phases of complex oxides exhibit distinct physical properties and show great potential in multifunctional devices. With the expected unique behaviors, however, most of the V-O-ordered oxide films are extremely difficult to synthesize due to their thermodynamic instabilities. Herein, using LaCoOx as an example, the synthesis of large-scale monophased V-O-ordered LaCoO2.67 and LaCoO2.5 films is realized by annealing as-grown perovskite LaCoO3 films in vacuum with a special heating method. Their macroscopic properties, including the magnetic and electric transport and optical properties, are measured. It is demonstrated that the functionalities of LaCoOx films can be manipulated by tuning the concentration and ordering of the V-O. The method in this work can be applied to fabricate a wide range of V-O-ordered oxide films.