Kenji Kisoda

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We have grown BiFeO(3) bulk single crystals by a flux method and characterized the phonon spectra in detail by Raman scattering in the temperature range 4-1100 K. All the 13 Raman-active phonon modes predicted by group theory, 4A(1)+9E, were observed at low temperature and successfully assigned by a polarized Raman measurement. Moreover, drastic spectral(More)
Thin films of chiral porphyrin J-aggregates have been studied by vibrationally and electronically doubly resonant sum frequency generation (SFG) spectroscopy. It was revealed that the chiral supramolecular structures of porphyrin aggregates in solutions were retained in the thin film samples, and their chirality was determined by using chiral vibrational(More)
Hexagonal YbMnO(3) bulk polycrystals were prepared and studied by Raman scattering in the temperature range of 15-300 K. A total of 15 phonon modes of A(1), E(1) and E(2) type were identified. Some E(2) phonon modes showed anomalous temperature variations in frequency at T(N)∼80 K, suggesting a coupling between the spin and phonon systems below T(N). As(More)
YMnO(3) is a multiferroic material in which ferroelectric and antiferromagnetic ordering can coexist. We have studied a YMnO(3) bulk crystal in detail by Raman scattering in a wide temperature range of 15-1200 K, with comparison to a previous experiment at room temperature and a theoretical prediction for Raman-active phonon modes. In the low-temperature(More)
Low-temperature formation processes of Ni silicide were studied by Raman scattering and cross-sectional transmission electron microscopy (TEM) using Si wafer samples deposited with thin Ni layers. Comparisons were made between two annealing methods; cold wall, lamp based rapid thermal process (lamp RTP) and a hot wall chamber RTP system. . The TEM and Raman(More)
TiO(2) nanocrystals were synthesized by a hydrolysis method combined with a thermal treatment. TiO(2) nanocrystals with rutile and anatase structure were selectively synthesized by controlling the pH level in the precursor solution, and the crystallite size was controlled by changing the reaction temperature. Moreover, Co-doped TiO(2) nanocrystals with(More)
Nanometre-sized ZnO crystals doped with Co were synthesized by a co-precipitation method combined with a thermal treatment. By changing the reaction temperature, we can control the crystallite size from roughly 10 nm particles to 20 nm × 200 nm nm rods grown along the hexagonal c-direction. X-ray diffraction and Raman scattering showed growth of(More)
Precise control of fabrication processing is a key point for future integration technology of Si devices. Reliable characterization of Si wafers at each fabrication process is indispensable. Raman scattering has high-potential as a technique for noncontact and nondestructive characterization which yields valuable information on Si-based materials. Here, a(More)
Ho(3)Fe(5)O(12) crystallizes in a body-centered cubic lattice and shows no ferroelectricity because of its highly symmetric (centrosymmetric) crystal structure. However, in heteroepitaxially grown thin films, Ho(3)Fe(5)O(12) may exhibit ferroelectricity because of lattice strains induced by the substrate. In this work, heteroepitaxial films of(More)
Zn(1-x)Co(x)O samples were prepared by a standard solid-state reaction method. Zn(1-x)Co(x)O crystals in the wurtzite structure were obtained with a Co composition of up to 22.1%. The a- and c-axis lengths increased and decreased, respectively, with an increase in Co composition. Raman spectra showed systematic broadening of the E(2) (high) phonon mode(More)
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