Nano-Domain and Defect Engineering of Binary and Ternary-modified PMN-PT Textured Ceramics and Crystals
Abstract
Domain boundaries typically constitute only a minute fraction of the total volume of a crystal.However, a special (but not usual) situation can occur in which the domain boundary energybecomes very small. Specifically, the domain size is miniaturized to near atomic scales and thedomain boundary density becomes extremely high. In such cases, the properties of the crystalbecome dominated by a combination of both the domains and the domain boundaries. Thisphenomenon differs from most ferroelectric materials wherein the motion of the domainboundaries dominates the response. The ability to control the nano-domain distribution and theself-assembly process is what we mean by the term nano-domain engineering.Here, we focus on one such specific state found in PMN-yPT (1-yPb(Mg1/3Nb2/3)O3-yPbTiO3)single crystals for composition close to the morphotropic phase boundary (MPB) ~ namely, theadaptive ferroelectric state. This state is characterized by a hierarchial domain structure extendingover length scales from nm to macroscopic shapes that self-assembles to achieve elastic invariantconditions. In this state, the properties of the twin boundaries represent the principal contributorsto the functionality. Adding to this complication is the fact that ternary substitutents and defectscan interact with either the domain or domain wall. High densities of walls, local site symmetriesnear defects, and topologically constrained dopants can all alter the functionality.In this proposal, we offer a nano-domain and defect/dopant engineering approach to binaryand ternary PMN-yPT textured ceramics and single crystals. Ternary solid solutions will beinvestigated, including xPb(In1/2Nb1/2)O3-(1-x-y)PMN-yPT (PIN-PMN-PT), Fe-doped PMN-PT,and Mn-doped PMN-PT. Investigations would include structural studies by x-ray diffraction,electron microscopy, high resolution electron microscopy, scanning probe microscopy, localcompositional probe analysis, and bulk property characterizations.The goal of the program is to determine how domain engineering and defects/dopants fromternary species alter nano-twin assembly into hierarchial domains, and whether defects/dopantscan be topological to the domain walls. Specifically, we hope to develop new generations of binaryand ternary textured ceramics and crystals by:(i) functionalization of their boundaries by defects and dopants; (ii) high domain wall densities that are controllable via nanodomain engineering; and (iii) how these characteristics are altered by lattice plane mismatches along the out-of-plane direction in textured ceramics, with the goal of controlling the hysteretic losses and piezoelectric anisotropy.This approach offers the potential to increase the coercive field, mechanical quality factor,dielectric and piezoelectric properties, in addition to the phase transformation temperature belowwhich a poled condition can be maintained. These are important and relevant issues to increasing the operational temperature range and duty cycle of high power sonar and highly sensitivity sensors for Navy applications; and transitioning the materials
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 03, 2017
- Source ID
- N000141712234
Entities
People
- Jie-fang Li
Organizations
- Office of Naval Research
- United States Navy
- Virginia Tech