Formation of High-Quality, Epitaxial La2Zr2O7Layers on Biaxially Textured Substrates by Slot-Die Coating of Chemical Solution Precursors

Abstract

Crystallization studies were performed of epitaxial La{sub 2}Zr{sub 2}O{sub 7} (LZO) films on biaxially textured Ni-3at.%W substrates having thin Y{sub 2}O{sub 3} (10 nm) seed layers. LZO films were deposited under controlled humid atmosphere using reel-to-reel slot-die coating of chemical solution precursors. Controlled crystallization under various processing conditions has revealed a broad phase space for obtaining high-quality, epitaxial LZO films without microcracks, with no degradation of crystallographic texture and with high surface crystallinity. Crack-free and strong c-axis aligned LZO films with no random orientation were obtained even at relatively low annealing temperatures of 850-950 C in flowing one atmosphere gas mixtures of Ar-4% H2 with an effective oxygen partial pressure of P(O2){approx}10{sup -22} atm. Texture and reflection high-energy electron diffraction analyses reveal that low-temperature-annealed samples have strong cube-on-cube epitaxy and high surface crystallinity, comparable to those of LZO film annealed at high temperature of 1100 C. In addition, these samples have a smoother surface morphology than films annealed at higher temperatures. Ni diffusion rate into the LZO buffer film is also expected to be significantly reduced at the lower annealing temperatures.