Vacancy-related defect profiles have been measured for La_(0.5)Sr_(0.5)CoO_(3)/(Pb_(0.9)La_(0.1))×(Zr_(0.2)Ti_(0.8))O_(3)/La_(0.5)Sr_(0.5)CoO_(3) ferroelectric capacitors using a variable-energy positron beam. By varying the layer thickness and the postgrowth processing in a reducing ambient, a capacitor showing oxygen deficiency dominantly in the top electrode and one with deficiency in both electrodes were produced. The capacitor with an asymmetric defect profile showed a voltage offset polarization-voltage hysteresis loop, that with a symmetric distribution of vacancy-related defects showed no offset. These results are discussed in the context of current models for imprint.
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