EFFECTS OF AMBIENT GAS-PRESSURE ON (1-X)SRTIO3-XBATIO(3) FILMS PREPARED BY PULSED-LASER DEPOSITION

Ambient gas pressure in pulsed laser deposition process has been obser ved to significantly modify the lattice parameters of (Sr1-xBax)TiO3 t hin films. The lattice parameters a(0) of the films deposited under lo w ambient pressure regime (P less than or equal to 0.01 mbar) were lar ger than those found on the films grown under high ambient pressure re gime (P greater than or equal to 0.1 mbar), regardless of the thin fil m composition (i.e., x value), substrate materials (Pt/Si or Si), or a mbient gas species (O-2 or N-2). It is proposed from these observation s that the large lattice parameters a(0) of the films grown under low- pressure environment result from higher concentration of vacancies, wh ich, in turn, are induced by the bombardment of energetic species ejec ted by laser beams. (C) 1996 American Institute of Physics.