Papers by Keyword: Inelastic X-Ray Scattering

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Authors: J. Serrano, J. Strempfer, M. Cardona, M. Schwoerer-Böhning, H. Requardt, M. Lorenzen, B. Stojetz, P. Pavone, Wolfgang J. Choyke
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Authors: Shinya Hosokawa, Masanori Inui, Yukio Kajihara, Tetsu Ichitsubo, Kazuhiro Matsuda, Hidemi Kato, Ayano Chiba, Koji Kimura, Kenji Kamimura, Satoshi Tsutsui, Hiroshi Uchiyama, Alfred Q.R. Baron
Abstract: To clarify microscopic elastic properties of a Pd40Ni40P20 bulk metallic glass, inelastic X-ray scattering (IXS) experiments were carried out using high-resolution IXS spectrometer installed at BL35XU/SPring-8. Clear longitudinal acoustic (LA) excitation modes are observed in the whole momentum transfer Q range up to ~22 nm-1. The microscopic sound velocity of the LA modes obtained from the Q → 0 limit of the dispersion relation is about 12% faster than the macroscopic value, suggesting the microscopic heterogeneity in the elastic properties of this BMG. In addition, transverse acoustic (TA) modes can be deduced from a detailed analysis of the IXS spectra. The microscopic Poisson’s ratio obtained from the ratio of the excitation energies of the TA and LA modes is 0.47 ± 0.04, larger than the macroscopic value of 0.40. Thus, the fragile nature of this BMG already found in the macroscopic sense is much enhanced in the microscopic view.
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Authors: Dieter Strauch, B. Dorner, A.A. Ivanov, M. Krisch, J. Serrano, Alexey Bosak, Wolfgang J. Choyke, B. Stojetz, Michael Malorny
Abstract: Preliminary results for the phonon dispersion curves of hexagonal 4H-SiC from experimental inelastic neutron (INS) and X-ray scattering (IXS) are reported and contrasted with those of cubic 3C-SiC and silicon. The experimental frequencies and scattering intensities are in excellent agreement with those from first-principles calculations using density-functional methods. The relative merits of the two experimental techniques and aspects of the density functional perturbation theory and the so-called frozen phonon method for the determination of the basic phonon properties are briefly outlined.
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