Pulsed laser deposition of PbMg_(1/3)Nb_(2/3)O_3 thin films and PbMg_(1/3)Nb_(2/3)O_3/PbTiO_3 multilayers

摘要

We have fabricated epitaxial thin films of the relaxor Pb(Mg_(1/3)Nb_(2/3))O_3 (PMN) and multilayer structures of relaxor/ferroelectric Pb(Mg_(1/3)Nb_(2/3))O_3/PbTiO_3 (PMN/PTO) using pulsed laser deposition. We present results obtained using reflection high energy electron diffraction (RHEED), x-ray diffraction (XRD) and transmission electron microscopy (TEM) on thin films of PMN grown on single crystal (100) SrTiO_3 substrates using a stoichiometric PMN ceramic target and a PMN-2%Mg target. With the latter target we were able to produce pyrochlore free thin films. RHEED images 140A PMN films consist of sharp lines and Kikuchi bands which indicate smooth surfaces. This is borne out by the observation of XRD Laue (thickness) oscillations. TEM images of PMN films with some pyrochlore show the PMN growth is columnar and the widths are on the order of 400A. Multilayer structures of (PMN_(Λ/2)/PTO_(Λ/2))_4 (Λ is the modulation period) were sucessfully grown. Satellite peaks were observed for these quadrilayer structures and preliminary analysis indicates that for the majority of the tetragonal PTO layers are oriented with the c-axis in the plane of the film.