AVS 51st International Symposium
    Electronic Materials and Processing Thursday Sessions
       Session EM-ThA

Paper EM-ThA4
Strain-effected Phase Transition Temperature of BST Thin Films

Thursday, November 18, 2004, 3:00 pm, Room 304B

Session: Multifunctional Materials
Presenter: J.A. Bellotti, Naval Research Laboratory
Authors: J.A. Bellotti, Naval Research Laboratory
W. Chang, Naval Research Laboratory
S.B. Qadri, Naval Research Laboratory
S.W. Kirchoefer, Naval Research Laboratory
J.M. Pond, Naval Research Laboratory
Correspondent: Click to Email
Ba@sub 0.5@Sr@sub 0.5@TiO@sub 3@ (BST) thin films were grown on (100) MgO and (100) LaAlO@sub 3@ substrates by rf/magnetron sputtering in the thickness range of 50 to 300 nm. Recent studies have demonstrated the importance of film strain on the microwave frequency electronic properties of ferroelectric thin films. We have observed that stress can result in Curie temperature shifts of nearly 300 K in epitaxial thin films of SrTiO@sub 3@@footnote 1@. These highly strained films are also shown to have large directional dependences on the applied electric field. We report on efforts to relate lattice spacing and the resultant substrate-induced stress, as measured by x-ray diffraction, with the measured Curie temperature and microwave tunability and loss. XRD phase analysis as a function temperature will be correlated with the observed directionally-dependent and temperature-dependent microwave properties. Additional characterization of non-epitaxial films and bulk substrate crystals will be presented as a baseline for understanding the strain effect in thin ferroelectric layers. @FootnoteText@ @footnote 1@"Using Strain to Control Microwave Tunability and Loss in Barium Strontium Titanate Thin Films", AVS 50th International Symposium, Session EM-WeM5, Invited Talk, 2003. .