HYSTERESIS RELAXATION IN (PB,LA)(ZR,TI)O-3 THIN-FILM CAPACITORS WITH (LA,SR)COO3 ELECTRODES

We report on the thermally activated hysteresis relaxation effects in (La,Sr)CoO3/ (Pb,La)(Zr,Ti)O-3/(La,Sr)CoO3 thin film ferroelectric cap acitors. Films cooled in oxygen deficient ambients exhibit a marked vo ltage offset in the hysteresis loops. Upon the application of a dc bia s voltage or undirectional pulses of the same polarity as the offset, the loops become more symmetric. Subsequently, holding the capacitors in the original preferred polarization state leads to a relaxation of the hysteresis loop towards its original voltage offset condition. The relaxation process is described by a stretched exponential and is the rmally activated. (C) 1996 American Institute of Physics.