Piezoresponse imaging of lead zirconate titanate microfibers and numerical analysis of its electric field distribution

Piezoresponse imaging technique was transplanted from thin film to probe polarization domains and local properties in single electrospun lead zirconate titanate microfibers. The corresponding electric field distribution was numerically analyzed. The biased conic tip is found to produce a field that peaks on its apex and decreases rapidly toward the bottom metal electrode. A strong field exists only in a thin surface region and cannot pole the affected domain even with its magnitude of 108 V/m on the fiber surface. Comments Copyright 2007 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. Reprinted in Applied Physics Letters, Volume 91, Article 263108, December 2007, 3 pages. Publisher URL: http://dx.doi.org/10.1063/1.2827564 This journal article is available at ScholarlyCommons: http://repository.upenn.edu/ese_papers/319 Piezoresponse imaging of lead zirconate titanate microfibers and numerical analysis of its electric field distribution Yu Wang and Jorge Santiago-Avilés Department of Electrical and Systems Engineering, University of Pennsylvania, 200 South 33rd Street, Philadelphia 19104, USA Received 10 September 2007; accepted 1 December 2007; published online 28 December 2007 Piezoresponse imaging technique was transplanted from thin film to probe polarization domains and local properties in single electrospun lead zirconate titanate microfibers. The corresponding electric field distribution was numerically analyzed. The biased conic tip is found to produce a field that peaks on its apex and decreases rapidly toward the bottom metal electrode. A strong field exists only in a thin surface region and cannot pole the affected domain even with its magnitude of 108 V /m on the fiber surface. © 2007 American Institute of Physics. DOI: 10.1063/1.2827564 Lead zirconate titanate, Pb ZrxTi1−x O3 PZT , is a wellknown ferroelectric material with significant technological importance. PZT fibers have potential for utilization in high performance hydrophones and ultrasonic transducer applications. We synthesized PZT fibers with diameter from 100 nm to 20 m by means of electrospinning and metalloorganic decomposition. Since then, it has been a challenge for us to evaluate their ferroelectric properties. Usually, PZT is evaluated as dielectric media in a sandwiched metal/PZT/ metal capacitor. Such evaluation does not work for a single PZT fiber with diameter less than 10 m because of its ultralow capacitance. Recently, piezoresponse imaging PRI has been developed to probe polarization domains in ferroelectric thin films including PZT thin film , measure their properties in microor nano-scale, and correlate domain polarization and local properties directly with topography and morphology. PRI is realized through the combination of scanning probe microscopy SPM and lock-in electrical measurement techniques. It makes use of a sandwiched conductive SPM tip/PZT thin film/bottom metal capacitor, where the vertical SPM tip acts as the top electrode that can be precisely positioned and moved in a program-controlled way. dc and ac voltages Vdc and Vac cos t are applied simultaneously between the tip and the bottom metal, Vtip = Vdc + Vac cos t , 1 set up electric field E and induce piezoelectric oscillation