TEMPERATURE AND THICKNESS DEPENDENT EPITAXIAL RELATIONSHIP OF PD(111)ON CR(110)

Considering only the atomic diameter ratio, a Kurdjumov-Sachs (KS) in- plane epitaxial relationship between Pd(lll) and Cr(110) appears to be favored. However, depending up on growth temperature and film thickne ss we obtain both Nishiyama-Wassermann (NW) and KS orientations. This was found by surface X-ray scattering as well as from LEED experiments . The two orientations can be distinguished by the number of in-plane domains which is one for NW and two for KS. The samples were grown by MBE. During the Pd growth, we observe a continuous transition from the KS to the NW relationship, which is accompanied by a major reorientat ion of material. Qualitative considerations concerning the Pd island s tructure, which develops during growth, explain the observed behavior. The thickness-temperature dependence of the different epitaxial orien tations has been determined in a phase diagram. (C) 1998 Elsevier Scie nce S.A.