Browsing by Author "Suzuki, T"

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    Color centers in NaCl single crystals induced by pulsed intense relativistic electron beams to simulate radiation bursts in Europa
    (IOP Publishing, 2019-03-26) Toba, R; Kikuchi, K; Imada, G; Thorogood, GJ; Hayashi, N; Maynard-Casely, HE; Suematsu, H; Nakayama, T; Suzuki, T; Niihara, K
    To simulate the burst irradiation environment of Europa, single crystals of NaCl were irradiated by pulsed intense relativistic electron beams (PIREBs) with a peak energy of 6 MeV, a current of −800 A, and a pulse width of 70 ns. After irradiation, the optical absorption of the samples was measured, and results indicated that the irradiation induced F- and F2-centers. The density of F-centers was estimated to be 8.9 × 1016 cm−3 from 1 shot of PIREB irradiation with 6 MeV. The absorbed energy to form F-centers by PIREB was comparable but slightly higher than those induced by conventional direct current accelerators. The effect of pulsed heating, which should be taken into account for the detection of NaCl on Europa, is discussed. © 2019 The Japan Society of Applied Physics
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    Ground state of (Pb0.94Sr0.06)(Zr0.530Ti0.470)O3 in the morphotropic phase boundary region: evidence for a monoclinic Cc space group
    (American Physical Society, 2011-10-24) Solanki, RS; Singh, AK; Mishra, SK; Kennedy, SJ; Suzuki, T; Kuroiwa, Y; Moriyoshi, C; Pandey, D
    The antiferrodistortive (AFD) phase transition for a pseudotetragonal composition of Pb(Zr(0.530)Ti(0.470))O(3) doped with 6% Sr has been investigated using sound velocity (4-320 K), high-resolution synchrotron x-ray powder diffraction (100-800 K), and high-resolution as well as high-flux neutron powder diffraction measurements (4 K) to settle the existing controversies about the true ground state of Pb(Zr(x)Ti(1-x))O(3) (PZT) in the morphotropic phase boundary (MPB) region. The multiplet character of the neutron diffraction profiles of (3/2 1/2 1/2)(pc) (pseudocubic or pc indices) and (3/2 3/2 1/2)(pc) superlattice peaks, appearing below the AFD transition temperature, rules out the rhombohedral R3c space group. The true ground state is confirmed to be monoclinic in the Cc space group, in agreement with the predictions of the first-principles calculations and earlier findings for pure PZT in the MPB region. Here, 6% Sr(2+) substitution and the use of high-wavelength (lambda = 2.44 angstrom) neutrons have played a key role in settling the existing controversies about the true ground state of PZT in the MPB region. © 2011, American Physical Society
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    Microstructure of Cr (N,O) thin films studied by high resolution transmission electron microscopy
    (Elsevier, 2017-03-01) Suzuki, K; Suematsu, H; Thorogood, GJ; Suzuki, T
    In order to obtain insight into the hardening mechanism of Cr(N,O) thin films with respect to increase in oxygen content, the microstructure of Cr(N,O) grains in thin films was studied. High resolution transmission electron microscopy provided evidence that the grains in Cr(N,O) thin films prepared by pulsed laser deposition, which have an oxygen content of > 27 mol%, contained stacking faults. Phase identification via electron diffraction, indicated that the grains consisted of two phases, which had a NaCl-type and corundum-type structure and these phases had the same orientation as that of the Cr0.67O thin film. The estimated stacking fault energy of Cr(N,O) with an oxygen content of 34 mol% was 20 mJ/m2. Our results revealed the Cr(N,O) grains had the same nano-lamellar morphology as that of the Cr0.67O thin film which supports the possibility that the nano-lamellar morphology was formed by the introduction of extended dislocations. It is also possible that the hardening of Cr(N,O) was caused by dislocation pinning at the boundaries of the nano-lamellar morphology. © 2017 Elsevier B.V