A5056862327- Ferroelectric and Piezoelectric Materials
- Acoustic Wave Resonator Technologies
- Multiferroics and related materials
- Microwave Dielectric Ceramics Synthesis
- Semiconductor materials and devices
- Ferroelectric and Negative Capacitance Devices
- Perovskite Materials and Applications
Drexel University
2021-2023
University of California, Santa Barbara
2016-2021
Antiferroelectrics, which undergo a field-induced phase transition to ferroelectric order that manifests as double-hysteresis polarization switching, exhibit great potential for dielectric, electromechanical, and electrothermal applications. Compared their cousins, however, considerably fewer efforts have been made understand control antiferroelectrics. Here, it is demonstrated the switching behavior of an antiferroelectric can be strongly influenced effectively regulated by point defects....
The fabrication, measurement, and modeling of radio-frequency (RF), tunable interdigital capacitors (IDCs) are described. High quality factors 200 in the S/L-bands combined with a 47% tunability achieved by utilizing epitaxial (Ba,Sr)TiO3 films grown hybrid molecular beam epitaxy on LaAlO3 substrates. fabricated devices consisted one-port two-port IDCs embedded ground-signal-ground, coplanar waveguide transmission lines to enable RF probing. Wideband scattering parameters under bias were...
Domain walls separating regions of ferroelectric material with polarization oriented in different directions are crucial for applications ferroelectrics. Rational design materials requires the development a theory describing how compositional and environmental changes affect domain walls. To model wall systems, discrete microscopic Landau-Ginzburg-Devonshire (dmLGD) approach A- B-site cation displacements serving as order parameters is developed. Application dmLGD to classic BaTiO3 , KNbO3,...
Voltage-tunable, interdigital capacitors (IDCs) were fabricated on Ba0.29Sr0.71TiO3 grown by hybrid molecular beam epitaxy (MBE). In this growth technique, we utilize the metal-organic precursor titanium tetraisopropoxide rather than solid-source Ti as with conventional MBE. Two samples of varying BaxSr(1−x)TiO3 (BST) thicknesses and analyzed. High-quality, epitaxial Pt electrodes deposited sputtering from a high-purity target at 825 °C. The patterned etched argon ion milling, passivated...
This paper describes the fabrication, measurement, and modelling of radio-frequency (RF), tunable interdigital capacitors (IDC). The devices utilize electric-field Ba <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> Sr xmlns:xlink="http://www.w3.org/1999/xlink">(1-x)</sub> TiO xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> (BST) thin films grown by hybrid molecular beam epitaxy (MBE) on LaAlO (LAO) substrates, a first growth its kind....
This paper describes the fabrication and measurement of tunable, lumped-element parallel-plate capacitors (PPC). The devices utilize electric-field tunable Ba <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> Sr xmlns:xlink="http://www.w3.org/1999/xlink">(1-x)</sub> TiO xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> (BST) thin films grown by hybrid molecular beam epitaxy (MBE) on SrTiO (STO) substrates. A high-quality interface was...
Prediction of properties from composition is a fundamental goal materials science and can greatly accelerate development functional materials. It particularly relevant for ferroelectric perovskite solid solutions where compositional variation primary tool design. To advance beyond the commonly used Landau-Ginzburg-Devonshire density theory methods that despite their power are not predictive, we elucidate key interactions govern ferroelectrics using 5-atom bulk unit cells non-ground-state...