Jon F. Ihlefeld

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Piezoelectric materials, which convert mechanical to electrical energy and vice versa, are typically characterized by the intimate coexistence of two phases across a morphotropic phase boundary. Electrically switching one to the other yields large electromechanical coupling coefficients. Driven by global environmental concerns, there is currently a strong(More)
We demonstrate, for the first time, an all-dielectric metamaterial composite in the midinfrared based on micron-sized, high-index tellurium dielectric resonators. Dielectric resonators are desirable compared to conventional metallodielectric metamaterials at optical frequencies as they are largely angular invariant, free of Ohmic loss, and easily integrated(More)
The interest in plasmonic technologies surrounds many emergent optoelectronic applications, such as plasmon lasers, transistors, sensors and information storage. Although plasmonic materials for ultraviolet-visible and near-infrared wavelengths have been found, the mid-infrared range remains a challenge to address: few known systems can achieve(More)
Above-band-gap optical excitation produces interdependent structural and electronic responses in a multiferroic BiFeO(3) thin film. Time-resolved synchrotron x-ray diffraction shows that photoexcitation can induce a large out-of-plane strain, with magnitudes on the order of half of one percent following pulsed-laser excitation. The strain relaxes with the(More)
By utilizing an equilibrium processing strategy that enables co-firing of oxides and base metals, a means to integrate the lithium-stable fast lithium-ion conductor lanthanum lithium tantalate directly with a thin copper foil current collector appropriate for a solid-state battery is presented. This resulting thin-film electrolyte possesses a room(More)
Caroline S. Gorham,1 Khalid Hattar,2 Ramez Cheaito,1 John C. Duda,1,* John T. Gaskins,1 Thomas E. Beechem,2 Jon F. Ihlefeld,2 Laura B. Biedermann,2 Edward S. Piekos,2 Douglas L. Medlin,3 and Patrick E. Hopkins1,† 1Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904, USA 2Sandia National Laboratories,(More)
Dynamic control of thermal transport in solid-state systems is a transformative capability with the promise to propel technologies including phononic logic, thermal management, and energy harvesting. A solid-state solution to rapidly manipulate phonons has escaped the scientific community. We demonstrate active and reversible tuning of thermal conductivity(More)
We experimentally investigate the role of size effects and boundary scattering on the thermal conductivity of silicon-germanium alloys. The thermal conductivities of a series of epitaxially grown Si(1-x)Ge(x) thin films with varying thicknesses and compositions were measured with time-domain thermoreflectance. The resulting conductivities are found to be 3(More)
Eva H. Smith, ⇤ Jon F. Ihlefeld, Colin A. Heikes, † Hanjong Paik, Yuefeng Nie, ‡ Carolina Adamo, Tassilo Heeg, Zi-Kui Liu, and Darrell G. Schlom 6, § Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853 USA Department of Materials Science and Engineering and Department of Electrical and Computer Engineering, University of(More)