The influence of strain on the dielectric behavior of (Ba/sub x/Sr/sub 1-x/)Ti/sub 1+y/O/sub 3+z/ thin films grown by LS-MOCVD on Pt/SiO/sub 2//Si

The strain state and its coupling to dielectric behavior have been investigated for {100} BST thin films deposited on Pt/SiO/sub 2//Si at 640/spl deg/C. It is estimated from X-ray diffraction that the in-plane biaxial strain is approximately 0.7%. We postulate that this is of sufficient magnitude to confine any spontaneous polarization to the plane of the film. The thickness-corrected dielectric behavior perpendicular to the substrate for these samples shows evidence of coupling to such an in-plane phase transition at approximately 390 K, as manifested by deviation from Curie-Weiss-like behavior at this temperature.