Nanoscale atomic displacements
Researchers using the XSD 11-ID-C beamline at the APS have discovered that the nanoscale ordering of atomic displacements under a nonpolar electric field plays a central role towards enhanced piezoelectric properties of ABO3 ferroelectrics.
This critical insight provides a strong correlation between changes in nanoscale atomic displacements and increased lattice instability, which could be the key for enhancing functional properties of many lead-free ferroelectric compounds.
Ferroelectrics are used as electromechanical energy transducers in many technologies owing to their large piezoelectric properties, including sonar, medical diagnostic imaging, microfluidic biomedical devices, 3D printing, active vibration control and energy harvesting. Due to environmental concerns regarding the current lead-based ferroelectrics, there have been tremendous efforts in the last decade for search of lead-free alternatives.
In situ synchrotron X-ray diffuse scattering and inelastic neutron scattering measurements from a prototype ABO3 ferroelectric single-crystal are used to elucidate how electric fields along a nonpolar direction can enhance its piezoelectric properties. The central mechanism is found to be a nanoscale ordering of B atom displacements, which induces increased lattice instability and therefore a greater susceptibility to electric-field-induced mechanical deformation.
Abhijit Pramanick, Mads R. V. Jørgensen, Souleymane O. Diallo, Andrew D. Christianson, Jaime A. Fernandez-Baca, Christina Hoffmann, Xiaoping Wang, Si Lan and Xun-Li Wang, “Nanoscale Atomic Displacements Ordering for Enhanced Piezoelectric Properties in Lead-Free ABO3 Ferroelectrics,” Advanced Materials, DOI: 10.1002/adma.201501274. Published Online June 15, 2015.