Takahama, Ryusei*; Ishii, Toi*; Indo, Daigo*; Arizono, Mitsutoshi*; Terakura, Chieko*; Tokura, Yoshinori*; Takeshita, Nao*; Noda, Masaaki*; Kuwahara, Hideki*; Saiki, Takuo*; et al.
Physical Review Materials (Internet), 4(7), p.074401_1 - 074401_11, 2020/07
Sato, Yusuke*; Fukaya, Yuki; Cameau, M.*; Kundu, A. K.*; Shiga, Daisuke*; Yukawa, Ryu*; Horiba, Koji*; Chen, C.-H.*; Huang, A.*; Jeng, H.-T.*; et al.
Physical Review Materials (Internet), 4(6), p.064005_1 - 064005_6, 2020/06
no abstracts in English
Guguchia, Z.*; Frandsen, B. A.*; Santos-Cottin, D.*; Shamoto, Shinichi; Gauzzi, A.*; Uemura, Yasutomo*; 12 of others*
Physical Review Materials (Internet), 3(4), p.045001_1 - 045001_9, 2019/04
We have studied the Mott transition of BaCoS by pressure and Ni substitution using SR, and examined the appearance of the quantum phase transition. The results show that both quantum phase transitions are first-order transitions at zero temperature.
Wakabayashi, Yuki*; Nonaka, Yosuke*; Takeda, Yukiharu; Sakamoto, Shoya*; Ikeda, Keisuke*; Chi, Z.*; Shibata, Goro*; Tanaka, Arata*; Saito, Yuji; Yamagami, Hiroshi; et al.
Physical Review Materials (Internet), 2(10), p.104416_1 - 104416_12, 2018/10
Amekura, Hiroshi*; Kluth, P.*; Mota-Santiago, P.*; Sahlberg, I.*; Jantunen, V.*; Leino, A. A.*; Vazquez, H.*; Nordlund, K.*; Djurabekova, F.*; Okubo, Nariaki; et al.
Physical Review Materials (Internet), 2(9), p.096001_1 - 096001_10, 2018/09
When a swift heavy ion (SHI) penetrates amorphous SiO, a core/shell (C/S) ion track is formed due to vaporization, where the ion track consists of a lower-density core and a higher-density shell. Here we reexamine this hypothesis. The MD simulations indicate that the vaporization is not induced under 50-MeV Si irradiation ( = 3 keV/nm), but the C/S tracks and the ion shaping of nanoparticles are nevertheless induced. Thus, the vaporization is not a prerequisite for the C/S tracks and the ion shaping.
Takata, Fumiya*; Ito, Keita*; Takeda, Yukiharu; Saito, Yuji; Takanashi, Koki*; Kimura, Akio*; Suemasu, Takashi*
Physical Review Materials (Internet), 2(2), p.024407_1 - 024407_5, 2018/02
Matsumoto, Takahiro*; Ohara, Takashi; Sugimoto, Hidehiko*; Bennington, S. M.*; Ikeda, Susumu*
Physical Review Materials (Internet), 1(5), p.051601_1 - 051601_6, 2017/10
Physical Review Materials (Internet), 1(3), p.033604_1 - 033604_5, 2017/08
A new mechanism of anomalous tension/compression (T/C) asymmetry in ultrafine-grained (UFG) metals is proposed using large-scale atomistic simulations and dislocation theory. Unlike coarse-grained metals, UFG Al exhibits remarkable T/C asymmetry of the yield stress. The atomistic simulations reveal that the yield event is not related to intragranular dislocations but caused by dislocation nucleation from the grain boundaries (GBs). The dislocation core structure associated with the stacking fault energy in Al is strongly affected by the external stress compared with Cu; specifically, high tensile stress stabilizes the dissociation into partial dislocations. These dislocations are more likely to be nucleated from GBs and form deformation twins from an energetic viewpoint. The new mechanism, which is completely different from well-known mechanisms for nanocrystalline and amorphous metals, is unique to high-strength UFG metals and can explain the difference in T/C asymmetry between UFG Cu and Al.
Winter, I. S.*; Tsuru, Tomohito; Chrzan, D. C.*
Physical Review Materials (Internet), 1(3), p.033606_1 - 033606_9, 2017/08
A first-principles investigation of the influence of lattice softening on lithium-magnesium alloys near the body-centered-cubic (bcc)/hexagonal close-packed (hcp) transition composition is presented. Results show that lithium-magnesium alloys display a softening of the shear modulus , and an acoustic phonon branch between the and high symmetry points, as the composition approaches the stability limit for the bcc phase. This softening is accompanied by an increase in the size of the dislocation core region. Ideal tensile strength calculations predict that ordered phases of lithium-magnesium alloys are intrinsically brittle. Methods to make the alloys more ductile are discussed, and the propensity for these alloys to display gum-metal-like behavior is assessed.