Epitaxial Relations in Films of Cr, Pt, and CrPt on Sapphire

Polycrystalline Cr-Pt thin film couples deposited on c-axis sapphire by vacuum evaporation have been found to be epitaxially oriented with respect to the substrates and to one another. The following crystallographic relationships were derived: (110)Cr//(001)sapphire with [110]Cr//a axis sapphire, (lll)Pt//(110)Cr with [112]Pt//[110]Cr. Upon annealing at about 1000C the films interdiffused to form a homogeneous CrPt film with two dominating orientations (100) and (111) which are epitaxially related to the original films. The (111) structure of CrPt has the same crystallographic characteristics as Pt. For the (100) orientation of CrPt the following relations are obeyed: (100)CrPt//(110) Cr with [010]CrPt//[111]Cr. None of these films could have been a single crystal, since symmetry considerations dictate that several crystallographically identical structures should coexist. © 1979, The Electrochemical Society, Inc. All rights reserved.