Relaxor ferroelectrics are characterized by some striking anomalous properties. For instance, they adopt a (frequency-dependent) peak in their ac dielectric response-versus-temperature function while they remain macroscopically paraelectric and cubic down to the lowest temperatures. Furthermore, this dielectric response deviates from the ``traditional'' Curie-Weiss law for temperatures lower than the so-called Burns temperature. Other examples of anomalous properties include the plateau observed in their static, dc dielectric response at low temperature, and the unusual temperature behavior of the Edwards-Anderson parameter. Determining the origin of these intriguing effects has been a challenge to scientists for more than half a century. The aim of this talk is to report and discuss results of atomistic simulations [1-10] that not only reproduce anomalous features of relaxors but also offer a microscopic insight into the Ba(Zr,Ti)O3 and Pb(Mg,Nb)O3 relaxor ferroelectrics.
References
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