Detection of a Pd-Ni interlayer at the Pd/Ni interface of an epitaxial Pd film on cube textured nickel (001)

Abstract

We studied the microstructure of a Pd overlayer deposited on a cube textured Ni(0 0 1) substrate using synchrotron X-ray scattering. We find the existence of an epitaxial Pd-Ni interlayer between the epitaxial Pd layer and the Ni substrate. The Pd-Ni interlayer, which is compressively strained in a manner similar to the Pd overlayer, seemingly acts to relieve the strain at the Pd/Ni interface caused by the Pd-Ni lattice mismatch. The Ni mosaic distribution of our samples is multiply spiked with a rocking angle spread of similar to16degrees, which reconciles the previously reported observation of saw tooth peaks on top of a Gaussian distribution for a similarly prepared I'd on Ni specimen. The observed sharpening of the mosaic distributions for the Pd(0 0 2) grains (full-width at half-maximum (FWHM) = 1.95degrees) and for the (0 0 2) grains of Pd-Ni interlayer (FWHM = 3.0degrees) indicates that the Pd and Pd-Ni(0 0 2) layers conform to the surface morphology instead of to the (0 0 1) crystallographic planes of Ni-substrate grains. (C) 2002 Elsevier Science B.V. All rights reserved.