Low field depoling phenomena in soft lead zirconate titanate ferroelectrics
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Reduction in polarisation of ferroelectric materials due to repeated electrical cycling is a major problem in ferroelectric non-volatile memory devices. There is a large amount of data addressing this issue at high electric field strengths under bipolar loading conditions, however the effect of field cycling at low electric field strengths (< Ec) has not been fully investigated. This paper addresses the effects of repeated cycling of soft lead zirconate titanate using electrical pulses at fields well below the coercive field strength of the material. It is shown that this mode of loading diminishes the macroscopic polarisation and mechanical response of the material. The origins of this behaviour are found to be a statistical non-non-reversible switching processes that does not result in classical fatigue related mechanical microstructural damage or defect agglomeration and domain pinning. Instead the process is fully recoverable and attributed to local changes in switching energy and clustering of switched ferroelectric cells.
KeywordsFerroelectrcis PZT Depoling Fatigue Fram Feram Lead-zirconate-titanate
The financial support of the UK’s Engineering and Physical Sciences Research Council via the Centre for Doctoral Training in Micro and Nano Materials and Technology at the University of Surrey and the UK’s National Measurement Office is gratefully acknowledged.
The authors confirm that all data underlying the findings are fully available without restriction. Details of the data and how to request access are available from: http://dx. doi.org/10.15126/surreydata.00811053
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