Browsing by Author "Ruette, Benjamin"

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    Dramatically enhanced polarization in (001), (101), and (111) BiFeO3 thin films due to epitiaxial-induced transitions
    Li, Jiefang; Wang, Junling; Wuttig, Manfred; Ramesh, R.; Wang, Naigang; Ruette, Benjamin; Pyatakov, Alexander P.; Zvezdin, Anatoly Konstantinovich; Viehland, Dwight D. (AIP Publishing, 2004-06-01)
    Dramatically enhanced polarization has been found for (001), (101), and (111) films, relative to that of BiFeO3 crystals. The easy axis of spontaneous polarization lies close to (111), for the various oriented films. BiFeO3 films grown on (111) have a rhombohedral structure, identical to that of single crystals; whereas films grown on (101) or (001) are monoclinically distorted from the rhombohedral structure, due to the epitaxial constraint. (C) 2004 American Institute of Physics.
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    Magnetic-field-induced phase transition in BiFeO3 observed by high-field electron spin resonance: Cycloidal to homogeneous spin order
    Ruette, Benjamin; Zvyagin, Sergei; Pyatakov, Alexander P.; Bush, A.; Li, Jiefang; Belotelov, V. I.; Zvezdin, Anatoly Konstantinovich; Viehland, Dwight D. (American Physical Society, 2004-02-27)
    Bismuth ferrite is a magnetoelectric material, which simultaneously has polarization and spin orders. We have used electron spin resonance (ESR) as a local probe of the magnetic order in the magnetic-field range of 0-25 T, in the frequency domain of 115-360 GHz, and at a temperature of 4.2 K. The data reveal significant changes in the ESR spectra with increasing field, which have been analyzed by taking into account the magnetic anisotropy of the crystal and a magnetoelectric Dzyaloshinsky-Moria-like interaction. The results demonstrate an induced phase transition from an incommensurately cycloidal modulated state to one with homogeneous spin order.
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    Observation of domain texture in poled Pb(Mg1/3Nb2/3)O-3-PbTiO3 crystals
    Li, Jiefang; Ruette, Benjamin; Viehland, Dwight D. (AIP Publishing, 2002-11-01)
    Mapping of domain distributions under constant Bragg conditions has been performed on poled (0.7)Pb(Mg1/3Nb2/3)O-3-0.3PbTiO(3) crystals. Studies were done on crystals of cubic geometry, where each cube face was oriented along a [001](c). Multiple domains with monoclinic limiting symmetry (angle similar to173degrees-176degrees) were observed on all three (001)(c) faces. Perpendicular to the poling direction, domain modulations were observed by a splitting of each variant. (C) 2002 American Institute of Physics.