Browsing by Author "Harris, Vincent G."

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    Domain rotation induced strain effect on the magnetic and magneto-electric response in CoFe2O4/Pb(Mg,Nb)O-3-PbTiO3 heterostructures
    Wang, Zhiguang; Viswan, Ravindranath; Hu, Bolin; Li, Jiefang; Harris, Vincent G.; Viehland, Dwight D. (American Institute of Physics, 2012-02-01)
    The present work shows good control of both magnetic and electric properties with electric and magnetic fields, respectively, for epitaxial CoFe2O4 (CFO) films on Pb(Mg,Nb)O-3-PbTiO3 (PMN-PT). X-ray reciprocal space mapping revealed a transformation between a- and c-domains in the PMN-PT under electric field (E). Magnetic hysteresis loop and magnetic force microscopy (NM) measurements showed a considerable change in the magnetic properties in specific areas of CFO layers poled by MFM probe tips. Furthermore, a pulsed electric field applied to the substrate was found to switch the magnetization of CFO between high and low values, depending on the polarity of E. (C) 2012 American Institute of Physics. [doi: 10.1063/1.3684546]
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    Epitaxial growth of Pb(Zr0.53Ti0.47)O-3 films on Pt coated magnetostrictive amorphous metallic substrates toward next generation multiferroic heterostructures
    Hu, Bolin; Chen, Yajie; Yang, Aria F.; Gillette, Scott M.; Fitchorov, Trifon; Geiler, Anton L.; Daigle, Andrew; Su, X. D.; Wang, Zhiguang; Viehland, Dwight D.; Harris, Vincent G. (American Institute of Physics, 2012-03-15)
    Piezoelectric films of Pb(Zr0.53Ti0.47)O-3 (PZT) were deposited by pulsed laser deposition onto metallic magnetostrictive substrates. In order to optimize the growth of PZT films, a buffer layer of Pt was employed, as well as variation of deposition temperature, pressure, and laser energy. Room temperature 0-20 x-ray diffraction measurements indicate all diffraction features correspond to reflections indexed to a single PZT phase of space group P4mm. Scanning electron microscopy images reveal pinhole-free dense films of pyramidal shaped crystal arrangements whose orientation and size were controlled by variation of oxygen pressures during deposition. The resulting PZT films had a value of d(33) similar to 46 pm/V representing a 53% increase over previous efforts to realize a piezoelectric/Metglas (TM) film heterostructure. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3697605]
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    Magnetoelectric effect in crystallographically textured BaTiO3 films deposited on ferromagnetic metallic glass foils
    Wang, Zhiguang; Yan, Li; Yang, Yaodong; Li, Jiefang; Das, Jaydip; Geiler, Anton L.; Yang, Aria F.; Chen, Yajie; Harris, Vincent G.; Viehland, Dwight D. (American Institute of Physics, 2011-02-01)
    We demonstrate a significant control of the polarization response under an applied magnetic field for a magnetoelectric (ME) heterostructure. This structure was comprised of a 2 mu m thick ferroelectric BaTiO3 (BTO) film deposited on flexible ferromagnetic metallic glass foil (25 mu m thick). Au was used as a buffer layer to control BTO growth orientation, and to protect the metallic glass from oxidation. x-ray diffraction and scanning electron microscopy demonstrated the successful growth of well-crystallized BTO films with a high degree of (111) orientation on the amorphous metallic glass foils. Well-defined polarization (P-E) and magnetization (M-H) hysteresis loops confirmed the coexistence of ferroelectric and ferromagnetic properties. A ME voltage coefficient of about similar to 60 mV/cm Oe was measured. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3544352]
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    Piezoelectric properties of epitaxial Pb(Zr-0.525, Ti-0.475)O-3 films on amorphous magnetic metal substrates
    Hu, Bolin; Chen, Yajie; Yang, Aria F.; Gillette, Scott M.; Fitchorov, Trifon; Geiler, Anton L.; Daigle, Andrew; Su, X. D.; Wang, Zhiguang; Viehland, Dwight D.; Vittoria, Carmine; Harris, Vincent G. (American Institute of Physics, 2012-04-01)
    Epitaxial growth of high piezoelectric constant Pb(Zr-0.525, Ti-0.475)O-3 (PZT) thin films deposited on amorphous magnetic Metglas (R) substrates by pulsed laser deposition (PLD) is reported. Particularly, Pt or Au buffer layers were employed to initiate epitaxial growth of the PZT films from atop of an amorphous surface. The optimization of deposition conditions for the PZT films with different buffer layers was systematically investigated. The crystal structure, texturing, and surface morphology of the samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Ferroelectric and piezoelectric properties were measured indicating high polarization 27 mu C/cm(2) and piezoelectric constant d(33), 46 pm/V for the Pt buffered films. The PZT thin films grown on a magnetostrictive material have demonstrated high quality crystallographic structure and piezoelectric response, having potential for use in emerging magnetoelectric sensors. (C) 2012 American Institute of Physics. [doi:10.1063/1.3677864]