Abstract
The formation of polar nanoregions through solid-solution additions is known to enhance significantly the functional properties of ferroelectric materials. Despite considerable progress in characterizing the microscopic behavior of polar nanoregions (PNR), understanding their real-space atomic structure and dynamics of their formation remains a considerable challenge. Here, using the method of dynamic pair distribution function, we provide direct insights into the role of solid-solution additions towards the stabilization of polar nanoregions in the Pb-free ferroelectric of Ba(Zr,Ti)O3. It is shown that for an optimum level of substitution of Ti by larger Zr ions, the dynamics of atomic displacements for ferroelectric polarization are slowed sufficiently below THz frequencies, which leads to increased local correlation among dipoles within PNRs. The dynamic pair distribution function technique demonstrates a unique capability to obtain insights into locally correlated atomic dynamics in disordered materials, including new Pb-free ferroelectrics, which is necessary to understand and control their functional properties.
| Original language | English |
|---|---|
| Article number | 207603 |
| Journal | Physical Review Letters |
| Volume | 120 |
| Issue number | 20 |
| DOIs | |
| State | Published - May 18 2018 |
Funding
A. P. gratefully acknowledges funding support from a CityU Start-up Grant for New Faculty (Projects No. 7200514 and No. 9610377) and a CityU Teaching Start-up Grant (Project No. 6000590). A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. W. D., T. E., and J. M. B. were supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Science and Engineering Division. M. R. V. J. is grateful for the support by the Danish National Research Foundation (DNRF93), and the Danish Research Council for Nature and Universe (Danscatt). A. P. gratefully acknowledges technical assistance from Mr. Daniel Yau. A. P. acknowledges helpful discussion on this topic with Souleymane Omar Diallo.