Local structure and medium-range ordering in relaxor ferroelectric Pb(Zn1∕3Nb2∕3)O3 studied using neutron pair distribution function analysis

Abstract

We studied an evolution of local structure and medium-range ordering in relaxor ferroelectric Pb(Zn1∕3Nb2∕3)O3 (PZN) from 550 to 15K using neutron pair distribution function analysis. We show that the local structure of PZN is distorted at all temperatures studied. With decreasing temperature, a medium-range ordering of local polarizations develops with no global rhombohedral phase transition below TM. Instead, the crystal structure can be described as a mixture of polar nanoregions in a disordered lattice, similar to the case of Pb(Mg1∕3Nb2∕3)O3.