The effect of vanadium substitution in the Bi/sub 3.25/La/sub 0.75/Ti/sub 3/O/sub 12/ thin films grown by pulsed laser deposition

Vanadium doped Bi/sub 3.25/La/sub 0.75/Ti/sub 3/O/sub 12/ (BLTV) ferroelectric thin films are prepared on Pt(111)/Ti/SiO/sub 2//Si substrates by pulsed laser deposition. The structural and surface morphology are characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The ferroelectricity is confirmed by polarization-electric field (P-E) hysteresis loops. The ferroelectric properties of BLTV film is enhanced about 20% compared to that of BLT film. The remnant polarization (2P/sub r/) and coercive field (2E/sub C/) of BLTV film are 32 /spl mu/C/cm/sup 2/ and 150 kV/cm at the applied field of 200 kV/cm, respectively. The ac conductivity of the BLT and BLTV thin film capacitors are measured as a function of frequency (0.01 /spl sim/ 100 kHz) and temperature (25 /spl sim/ 300/spl deg/C) in order to investigate dielectric dispersion and conduction mechanism. The activation energy is estimated as 1.00 eV for BLT film and 0.56 eV for BLTV film from the slope of ac conductivity vs. 1/T plot at the low frequency and high temperature range. Also, electrical conduction behaviors are investigated by current-voltage (I-V) measurements as a function of applied electric fields. The vanadium doping effect on the BLT film is discussed in the relation to the ferroelectric properties and conduction behavior.