Neutron Scattering Study of the Relaxor Ferroelectric PZN -4.5{\%}PT under an [001]-Oriented Electric Field

Polar nano-regions (PNR) are believed to play important roles in determining many special properties of relaxor ferroelectric materials. We have performed a series of neutron diffuse scattering and neutron spin echo measurements on single crystals of Pb[(Zn$_{1/3}$Nb$_{2/3})_{0.955}$Ti$_{0.045}$]O$_{3 }$(PZN-4.5{\%}PT) to study the PNR under the influence of an [001] oriented electric field. Our results suggest that the short-range polar structure in this compound is complicated. In addition to the previously known PNR having $<$110$>$-oriented polarizations, we found PNR with $<$100$>$-oriented polarizations. The diffuse scattering intensity from $<$100$>$-oriented PNR can be partially suppressed by an external electric field applied along [001], while that from the $<$110$>$-oriented PNR exhibits little to no change. Our neutron spin echo measurements further show that the diffuse scattering intensity from the $<$100$>$-oriented PNR contains both static and dynamic components. On cooling, the static to dynamic ratio increases, suggesting that the short-range polar order freezes gradually.