Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Iida, Kazuki*; Yoshida, Hiroyuki*; Nakao, Akiko*; Jeschke, H. O.*; Iqbal, Y.*; Nakajima, Kenji; Kawamura, Seiko; Munakata, Koji*; Inamura, Yasuhiro; Murai, Naoki; et al.
Physical Review B, 101(22), p.220408_1 - 220408_6, 2020/06
Times Cited Count:19 Percentile:81(Materials Science, Multidisciplinary)Crystal and magnetic structures of the mineral centennialite CaCu(OD)Cl 0.6DO are investigated by means of synchrotron X-ray diffraction and neutron diffraction measurements complemented by density functional theory (DFT) and pseudofermion functional renormalization group (PFFRG) calculations. In CaCu(OD)Cl 0.6DO, Cu ions form a geometrically perfect kagome network with antiferromagnetic . No intersite disorder between Cu and Ca ions is detected. CaCu(OD)Cl 0.6DO enters a magnetic long-range ordered state below = 7.2 K, and the =0 magnetic structure with negative vector spin chirality is obtained. The ordered moment at 0.3 K is suppressed to 0.58(2)B. Our DFT calculations indicate the presence of antiferromagnetic and ferromagnetic superexchange couplings of a strength which places the system at the crossroads of three magnetic orders (at the classical level) and a spin- PFFRG analysis shows a dominance of =0 type magnetic correlations, consistent with and indicating proximity to the observed =0 spin structure. The results suggest that this material is located close to a quantum critical point and is a good realization of a -- kagome antiferromagnet.
Hiraishi, Masatoshi*; Iimura, Soshi*; Kojima, Kenji*; Yamaura, Junichi*; Hiraka, Haruhiro*; Ikeda, Kazutaka*; Miao, P.*; Ishikawa, Yoshihisa*; Torii, Shuki*; Miyazaki, Masanori*; et al.
Nature Physics, 10(4), p.300 - 303, 2014/04
Times Cited Count:101 Percentile:95.53(Physics, Multidisciplinary)Asai, Shinichiro*; Okazaki, Ryuji*; Terasaki, Ichiro*; Yasui, Yukio*; Kobayashi, Wataru*; Nakao, Akiko*; Kobayashi, Kensuke*; Kumai, Reiji*; Nakao, Hironori*; Murakami, Yoichi*; et al.
Journal of the Physical Society of Japan, 82(11), p.114606_1 - 114606_6, 2013/11
Times Cited Count:6 Percentile:43.6(Physics, Multidisciplinary)Neutron and synchrotron X-ray diffraction for LaCo RhO have been carried out in order to investigate the structural properties related with the spin state of Co ions. We have found that the values of the Co(Rh)-O bond lengths in the Co(Rh)O octahedron of LaCoRhO are nearly identical at 10 K. The lattice volume for the Rh substituted samples decreases with the thermal expansion coefficient similar to that of LaCoO from room temperature, and ceases to decrease around 70 K. These experimental results favor a mixed state consisting of the high-spin state and low-spin state Co ions, and suggest that the high-spin state Co ions are thermally excited in addition to those pinned by the substituted Rh ions.
Shirage, P. M.*; Miyazawa, Kiichi*; Ishikado, Motoyuki; Kiho, Kunihiro*; Lee, C.-H.*; Takeshita, Nao*; Matsuhata, Hirofumi*; Kumai, Reiji*; Tomioka, Yasuhide*; Ito, Toshimitsu*; et al.
Physica C, 469(9-12), p.355 - 369, 2009/06
Times Cited Count:40 Percentile:80(Physics, Applied)We have utilized a high-pressure (HP) technique to synthesize a series of newly-discovered iron (nickel)-based superconductors. The effect of (O)-deficiency, variation of ions, and the external pressure on are examined. All the experimental data indicate strong correlation between the crystal structure and the superconductivity of the oxypnictide superconductors. Upper critical field measurement on single crystalline sample of PrFeAsO shows the superconducting anisotropy of 5, which is smaller than cuprates. We also demonstrate that HP technique is applicable for the so-called "122" systems.