GROWTH OF FCC(111) ON BCC(110) - NEW-TYPE OF EPITAXIAL TRANSITION OBSERVED FOR PD ON CR

Depending on film thickness, t, and growth temperature, T, LEED and in -plane X-ray measurements show Kurdjumov-Sachs (KS) as well as Nishiya ma-Wassermann (NW) epitaxial relationships for Pd(lll) on Cr(110). Thi s is a surprising result, because theoretical models definitely expect the KS orientation for this system. In a systematic study of this phe nomenon we determined areas of different epitaxial orientations in a t -T diagram. During Pd growth, we observed a continuous transition from the KS to the NW epitaxial relationship, which is accompanied by an e normous reorientation of material. Qualitative considerations, concern ing the Pd island structure developing during growth, help to explain the observed behaviour. (C) 1998 Elsevier Science B.V.