Published online by Cambridge University Press: 26 February 2011
Quantitative high resolution transmission electron microscopy and x-ray diffraction have been used to study films of YBa2Cu3O7-δ grown on LaAlO3 substrates at low substrate temperatures. Based on analysis of high-resolution micrographs, it is asserted that the films are b-axis oriented near the film-substrate interface, and switch to a-axis oriented at some distance away from the interface, in a manner which varies from sample to sample. Thus, the films undergo a change in orientation as a function of distance from the substrate. X-ray diffraction confirms that these films contain both a-axis oriented and b-axis oriented components normal to the plane of the substrate, consistent with the high-resolution microscopy data.