UNCONVENTIONAL HYSTERESIS BEHAVIOR IN COMPOSITIONALLY GRADED PB(ZR,TI)O-3 THIN-FILMS

Thin-film lead-zirconate-titanate (PZT) capacitors with composition gr adients normal to the substrate were fabricated via a novel technique using pulsed laser deposition. These capacitors exhibited large polari zation offsets when driven by an alternating electric field. The direc tion of the offsets depended on the direction of the gradient with res pect to the substrate. The largest offset, greater than 400 mu C/cm(2) when driven with a 50 V/mu m field, was nearly an order of magnitude greater than any reported for other graded ferroelectric films. This d ifference is attributed to both the high spontaneous polarization of P ZT and the high-quality films obtained by pulsed laser deposition. (C) 1998 American Institute of Physics.