Electric-field-induced redistribution of polar nano-regions in a relaxor ferroelectric

Abstract

Relaxor ferroelectrics, with their strong dependence of polarization on the applied electric field, are of considerable technological importance. On a microscopic scale, however, there exists competition as well as coexistence between short-range and long-range polar order. The conventional picture is that the polar nano-regions (PNRs) that appear at high temperatures beyond the Curie transition, form nuclei for the field-induced long-range order at low temperatures. Here, we report high-energy X-ray diffuse-scattering measurements on the relaxor Pb(Zn(1/3)Nb(2/3))O(3) (PZN) to study the short-range polar order under an electric field applied along the [111] direction. In contrast to conventional expectations, the overall diffuse-scattering intensity is not suppressed. On the other hand, the field induces a marked change on the shape of the three-dimensional diffuse-scattering intensity pattern, corresponding to a redistribution of PNRs in real space. We show that these surprising results are consistent with a model in which the PNRs with [110]-type polarizations, orthogonal to that of the surrounding environment, are embedded and persist in the [111]-polarized ferroelectric order of the bulk.

Domain wall nanoelectronics

“…The presence of polar domains in the cubic phases of relaxors, where they are nominally forbidden, may be caused by flexoelectricity and internal strains due to local nonstoichiometry (Ahn et al, 2003). When mixed with ordinary ferroelectrics such as PbTiO 3 , or subjected to applied fields E, these nanodomains increase in size to become macroscopic (Mulvihill, Cross, and Uchino, 1995;Xu et al, 2006). As for the shape of the domains, in pure PbZn 1=3 Nb 2=3 O 3 (PZN), the domain walls may be spindlelike (Mulvihill, Cross, and Uchino, 1995) or dendritic (Liu, 2004) but become increasing lamellar with increasing additions of PbTiO 3 .…”

Lead-free and lead-basedABO3perovskite relaxors with mixed-valenceA-site andGe1, Devreugd2, Phelan3 et al. 2013Phys. Rev. B624490View full textAdd to dashboardCite

“…[12][13][14][15][16] These PNR have been linked to the unique anisotropic and temperature-dependent x-ray and neutron diffuse scattering patterns that have been observed in lead-based RFs. [17][18][19][20][21][22][23][24] For example, in the (HK0) scattering plane, the elastic diffuse scattering intensity forms butterfly-shaped contours near reciprocal lattice vectors of the form (h00) that feature prominent ridges that extend along [110] and [110], while the corresponding contours near (hh0) are ellipsoidal insofar as only a single ridge oriented along [110] is seen. In general, the contours near all reciprocal lattice points in the (HK0) scattering plane exhibit ridges that extend along one or more of the 110 directions.…”

Structural origins of relaxor behavior in a 0.96(Bi1/2Na1/2)TiO3–0.04BaTiO3 single crystal under electric field

“…17 The difference in the diffuse features of the two systems originates in the nature of the polarization; the polarization of the lead-containing materials is accompanied by a distortion of the unit cell and subsequent domain formation, whereas the polarization in BNT-BT occurs together with octahedral tilts that double the unit cell. Therefore, diffuse streaking due to the nanoregions in BNT-BT shows up at half order reflections.…”