Study of the microscopic structures in 0.72Pb(Mg1/3Nb2/3)O3-0.28PbTiO3 relaxor ferroelectrics by means of x-ray diffraction

X-ray diffraction experiment has been conducted to study the microscopic-scale structures for 0.72PMN-0.28PT relaxor ferroelectrics in a high external dc field during phase transition. Clear quasiperiodic structures were observed along < 111 > and < 1-11 > directions near T-C. These structures are interpreted as originating from strong Coulomb interactions among adjacent polar clusters. The projected cluster size (correlation length) was estimated to be 17 nm. It was also found that the dominating cluster's orientation and their interaction direction (periodic direction) were changeable among < 111 > and < 1-11 > as temperature changed. (c) 2007 American Institute of Physics.