Microscopic model of relaxor phenomena in Pb containing mixed oxides

The pulsed neutron atomic pair-density function (PDF) analysis of Ph contai ning ferroelectric oxides suggests that the local structure around Pb ion i s surprisingly independent of composition and crystal structure, and has a large electric dipole due to off-centering of Pb in the PbO12 cluster. This leads to a picture of interacting local dipolar moments through dipolar an d strain fields. Randomness of the interaction and the local strain fields due to mixed B-site ions can result in the relaxer behavior. Drawing upon t he knowledge on the random anisotropy ferromagnet and glass transition of a tomic glasses the origin of the relaxer ferroelectric phenomena will be dis cussed.