TRS Technologies

State College, PA, United States

TRS Technologies

State College, PA, United States

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Manley M.E.,Oak Ridge National Laboratory | Lynn J.W.,National Institute of Technology NIST | Abernathy D.L.,Oak Ridge National Laboratory | Specht E.D.,Oak Ridge National Laboratory | And 4 more authors.
Nature communications | Year: 2014

Relaxor ferroelectrics exemplify a class of functional materials where interplay between disorder and phase instability results in inhomogeneous nanoregions. Although known for about 30 years, there is no definitive explanation for polar nanoregions (PNRs). Here we show that ferroelectric phonon localization drives PNRs in relaxor ferroelectric PMN-30%PT using neutron scattering. At the frequency of a preexisting resonance mode, nanoregions of standing ferroelectric phonons develop with a coherence length equal to one wavelength and the PNR size. Anderson localization of ferroelectric phonons by resonance modes explains our observations and, with nonlinear slowing, the PNRs and relaxor properties. Phonon localization at additional resonances near the zone edges explains competing antiferroelectric distortions known to occur at the zone edges. Our results indicate the size and shape of PNRs that are not dictated by complex structural details, as commonly assumed, but by phonon resonance wave vectors. This discovery could guide the design of next generation relaxor ferroelectrics.


News Article | September 19, 2016
Site: www.cemag.us

The ORNL-led team was surprised to learn that the key to the impressive performance of relaxor-based ferroelectrics is the vibrations of tiny volumes of the material, called polar nanoregions, in which the positions of a few positive and negative ions shift slightly to create miniscule regions of electric polarization. The mechanical response of relaxor-based ferroelectric crystals is based on rotations of larger electrically aligned domains, about 20 microns in size. For these macroscopic regions of polarization to rotate, the atomic layers in the entire domain must displace around one another, or shear. Polar nanoregions as narrow as 2 nanometers are responsible for the enhanced electromechanical coupling (i.e., conversion of electrical to mechanical energy, and vice versa) that enables the dramatic improvements in piezoelectric applications by lowering the resistance to this shearing in the crystal. Understanding how polar nanoregions enhance material performance is relevant to the investigation of broad classes of chemically disordered materials beyond relaxor-based ferroelectrics, including shape-memory alloys, colossal magnetoresistors, magnetic semiconductors, and some superconductors. The new study used neutron scattering measurements of lattice dynamics and local structure to reveal the basis of the giant electromechanical coupling. Traditional ferroelectric materials are stiff; it is difficult for their large domains to rotate. But in ultra-responsive modern relaxor-based ferroelectrics, vibrations of the polar nanoregions mix with vibrations of the surrounding lattice to form hybrid vibrations. The hybrid vibrations result in a softer, low-energy shear, which makes it easier for the macroscopic regions of polarization to rotate. That means a larger mechanical response when an electric field is applied. “The point of this whole story is that it’s the interaction of these nanoregions with the average lattice which enables a larger mechanical response from a smaller field,” Manley says. Manley’s coauthors are Douglas Abernathy, Andrew Christianson, Paul Stonaha, Eliot Specht, and John Budai of ORNL; Raffi Sahul of TRS Technologies and Daniel Parshall and Jeffrey Lynn of the National Institute of Standards and Technology. Says Manley, “Next we’ll see if we can understand the limits of what can be done in terms of engineering elastic properties.” The title of the paper is “Giant electromechanical coupling of relaxor ferroelectrics controlled by polar nanoregion vibrations.” Portions of this work were conducted at the Spallation Neutron Source and High Flux Isotope Reactor, DOE Office of Science User Facilities at ORNL. The DOE Office of Science supported the work. The researchers also used neutron research facilities of the Department of Commerce’s National Institute of Standards and Technology. UT-Battelle manages ORNL for DOE’s Office of Science.


Luo J.,TRS Technologies | Zhang S.,Pennsylvania State University
Crystals | Year: 2014

Compared to Pb(Zr1-xTix)O3(PZT) polycrystalline ceramics, relaxor-PT single crystals offer significantly improved performance with extremely high electromechanical coupling and piezoelectric coefficients, making them promising materials for piezoelectric transducers, sensors and actuators. The recent advances in crystal growth and characterization of relaxor-PT-based ferroelectric single crystals are reviewed in this paper with emphases on the following topics: (1) the large crystal growth of binary and ternary relaxor-PT-based ferroelectric crystals for commercialization; (2) the composition segregation in the crystals grown from such a solid-solution system and possible solutions to reduce it; (3) the crystal growth from new binary and ternary compositions to expand the operating temperature and electric field; (4) the crystallographic orientation dependence and anisotropic behaviors of relaxor-PT-based ferroelectriccrystals; and (5) the characterization of the dielectric, elastic and piezoelectric properties of the relaxor-PT-based ferroelectriccrystals under small and large electric fields. © 2014 by the authors; licensee MDPI, Basel, Switzerland.


Lee H.J.,Pennsylvania State University | Zhang S.,Pennsylvania State University | Luo J.,TRS Technologies | Li F.,Pennsylvania State University | Shrout T.R.,Pennsylvania State University
Advanced Functional Materials | Year: 2010

The electrical properties of Pb(Mg1/3Nb2/3)O 3-PbTiO3 (PMN-PT)-based polycrystalline ceramics and single crystals were investigated as a function of scale ranging from 500 μm to 30 μm. Fine-grained PMN-PT ceramics exhibited comparable dielectric and piezoelectric properties to their coarsegrained counterpart in the low frequency range (<10 MHz), but offered greater mechanical strength and improved property stability with decreasing thickness, corresponding to higher operating frequencies (>40 MHz). For PMN-PT single crystals, however, the dielectric and electromechanical properties degraded with decreasing thickness, while ternary Pb(In1/2Nb1/2)O3- Pb(Mg 1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) exhibited minimal size-dependent behavior. The origin of property degradation of PMN-PT crystals was further studied by investigating the dielectric permittivity at high temperatures, and domain observations using optical polarized light microscopy. The results demonstrated that the thickness-dependent properties of relaxor-PT ferro- electrics are closely related to the domain size with respect to the associated macroscopic scale of the samples. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA.


Patent
TRS Technologies | Date: 2011-04-08

A piezoelectric composite micromachined ultrasound transducer including single and multilayer 1-D and 2-D arrays having through-wafer-vias (TWVs) that significantly decreased electrical impedance per element, and hence the improved electrical impedance matching to T/R electronics and improved signal to noise ratio is disclosed. The TWVs facilitate integrated interconnection in single element transducers (positive and negative contact on the same side) and array transducers (contact pads array for integration with T/R switches and/or pre-amplifier circuits).


Patent
TRS Technologies | Date: 2011-04-08

A piezoelectric composite micromachined ultrasound transducer including single and multilayer 1-D and 2-D arrays having through-wafer-vias (TWVs) that significantly decreased electrical impedance per element, and hence the improved electrical impedance matching to T/R electronics and improved signal to noise ratio is disclosed. The TWVs facilitate integrated interconnection in single element transducers (positive and negative contact on the same side) and array transducers (contact pads array for integration with T/R switches and/or pre-amplifier circuits).


Patent
TRS Technologies | Date: 2011-05-16

A ternary single crystal relaxor piezoelectric of PMN-PZ-PT grown from a novel melt using the Vertical Bridgeman method. The ternary single crystals are characterized by a Curie temperature, T_(c), of at least 150 C. and a rhombohedral to tetragonal phase transition temperature, T_(rt), of at least about 110 C. The ternary crystals further exhibit a piezoelectric coefficient, d_(33), in the range of at least about 1200-2000 pC/N.


Patent
TRS Technologies | Date: 2010-07-16

An antiferroelectric ceramic material that can be formed into a multilayer capacitor is disclosed. The antiferroelectric ceramic material is selected from the Pb(Sn, Zr, Ti)O3 (PSnZT) composition family.


Patent
TRS Technologies | Date: 2010-03-16

A <110> domain engineered relaxor-PT single crystals having a dielectric loss of about 0.2%, a high electromechanical coupling factor greater than about 85%, and high mechanical quality factor greater than about 500 is disclosed. In one embodiment, the relaxor-PT material has the general formula, Pb(B_(1)B_(2))O_(3)Pb(B_(3))O_(3), where B_(1 )may be one ion or combination of Mg^(2+), Zn^(2+), Ni^(2+), Sc^(3+), In^(3+), Yb^(3+), B_(2 )may be one ion or combination of Nb^(5+), Ta^(5+), W^(6+), and B_(3 )may be Ti^(4+) or combination of Ti^(4+) with Zr^(4+) and/or Hf^(4+).


The application is directed to piezoelectric single crystals having shear piezoelectric coefficients with enhanced temperature and/or electric field stability. These piezoelectric single crystal may be used, among other things, for vibration sensors as well as low frequency, compact sonar transducers with improved and/or enhanced performance.

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