Ferroelectricity of YMnO3 thin films prepared via solution

Abstract

We have observed the ferroelectricity at room temperature in YMnO3 thin films prepared via solution. Precursor films of YMnO3 on Pt/sapphire or Y2O3/Si substrates were heat treated in vacuum or in air for controlling the crystallinity. X-ray diffraction measurements indicated that each film was a single phase of hexagonal YMnO3. While the film heat treated in air indicated an insufficient crystallinity, the film heat treated in vacuum showed a high crystallinity with a c-axis preferred orientation. The leakage current of the film heat treated in vacuum was at least three orders of magnitude lower than that heat treated in air. The ferroelectricity of the film heat treated in vacuum was confirmed in the capacitance–voltage measurement at room temperature due to its high crystallinity with the c-axis preferred orientation and the small leakage current.