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arXiv · 1405.2306

The role of random electric fields in relaxors

D. Phelan·C. Stock·J. A. Rodriguez-Rivera·S. Chi·J. Leao·X. Long·Y. Xie·A. A. Bokov·Z. -G. Ye·P. Ganesh·P. M. Gehring
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Abstract

PbZr_{1-x}Ti_xO_3 (PZT) and Pb(Mg_{1/3}Nb_{2/3})_{1-x}Ti_xO_3 (PMN-$x$PT) are complex lead-oxide perovskites that display exceptional piezoelectric properties for pseudorhombohedral compositions near a tetragonal phase boundary. In PZT these compositions are ferroelectrics, but in PMN-xPT they are relaxors because the dielectric permittivity is frequency dependent and exhibits non-Arrhenius behavior. We show that the nanoscale structure unique to PMN-xPT and other lead-oxide perovskite relaxors is absent in PZT and correlates with a greater than 100% enhancement of the longitudinal piezoelectric coefficient in PMN-xPT relative to that in PZT. By comparing dielectric, structural, lattice dynamical, and piezoelectric measurements on PZT and PMN-xPT, two nearly identical compounds that represent weak and strong random electric field limits, we show that quenched (static) random fields establish the relaxor phase and identify the order parameter.

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D. Phelan, C. Stock, J. A. Rodriguez-Rivera, S. Chi, J. Leao, X. Long, Y. Xie, A. A. Bokov, Z. -G. Ye, P. Ganesh, P. M. Gehring. 2014-05-09. The role of random electric fields in relaxors. https://doi.org/10.1073/pnas.1314780111

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