Microscopic model of relaxor phenomena in Pb containing mixed oxides

The pulsed neutron atomic pair-density function (PDF) analysis of Ph containing ferroelectric oxides suggests that the local structure around Pb ion is surprisingly independent of composition and crystal structure, and has a large electric dipole due to off-centering of Pb in the PbO(12) cluster. This leads to a picture of interacting local dipolar moments through dipolar and 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 the knowledge on the random anisotropy ferromagnet and glass transition of atomic glasses the origin of the relaxer ferroelectric phenomena will be discussed.