A low-loss composition region identified from a thin-film composition spread of (Ba1-x-ySrxCay) TiO3

We have generated the thin-film ternary composition spread of (Ba1-x-ySrxCa y)TiO3 on an equilateral-triangle-shaped LaAlO3 substrate. Compositional va riation within the triangle was achieved by a precisely controlled shutter system inside a pulsed laser deposition chamber, which allows the depositio n of precursors with gradient thickness over the length of the substrate. A ppropriate postannealing afforded high-quality epitaxial thin films over al most the entire composition region. Mapping of the microwave dielectric pro perties of the composition-spread chip was performed using a scanning evane scent microwave microscope at 1 GHz. Composition region Ba0.12-0.25Sr0.35-0 .47Ca0.32-0.53TiO3 was found to have desirable properties for electronic ap plications. (C) 1999 American Institute of Physics. [S0003-6951(99)03508-1] .