|Masashi Mukaida||Last modified date：2019.06.24|
Professor / Functional Materials / Department of Materials Science and Engineering / Faculty of Engineering
|1.||Tetsuro Sueyoshi, Yasuya Iwanaga, Takanori Fujiyoshi, Yosuke Takai, Mitsuhiro Muta, Masashi Mukaida, Ataru Ichinose and Norito Ishikawa , Flux Pinning By Columnar Defects Along a-axis in a-axis Oriented YBCO Thin Films, ASC, 2018.09, [URL], Columnar defects (CDs) along a-axis were installed into an in-plane aligned a-axis-oriented YBa2Cu3Oy film by using heavy-ion irradiation, in order to clarify the influence of CDs on flux pin-ning properties around B || ab. The critical current density Jc at B || c significantly decreases after the irradiation, since the CDs act as a channel for flux creep along their length. In contrast, the in-troduction of CDs weakens the magnetic field dependence of Jc at B || ab, whereas there is little difference in the Jc for low magnetic fields before and after the irradiation. This means that the CDs can trap flux lines at B || ab, where naturally growth defects working as effective ab-correlated PCs exist. The trapping angle of CDs along the a-axis, on the other hand, is extremely narrow (~ 5.8) in comparison with CDs along the c-axis and is roughly coincides with other ab-correlated PCs. The small trapping angle of CDs along the a-axis is attributed to strong line tension energy of flux lines with elliptical core shape around B || ab. .|
|2.||A. Iwasaki, M. Muta, M. Arita, Y. Ikoma, M. Mukaida, A. Ichinose, The crystal nature of RE214 thin films depending on different temperature and oxygen pressure conditions, 日本金属学会九州支部・日本鉄鋼協会九州支部・軽金属学会九州支部 平成 29 年度合同学術講演会, 2019.06, A c-axis oriented thin film had best crystal nature at 20mTorr and 730℃. Its band gap was estimated to be 1.9eV. La_2 CuO_4 films might have the potential for light-absorbing layers. Therefore, further research is anticipated to discover more optimum condition where band gap is lower than 1.55eV..|
|3.||T. Sueyoshi, Y. Iwanaga, T. Fujiyoshi, Y. Takai, Masashi Mukaida, Angular behaviors of Jc in GdBCO coated conductors with columnar defects crossing to ab-plane, ASC, 2016.09, [URL], For REBa2Cu3Oy (RE: Rare Earth element, REBCO)-based coated conductors, effective pinning centers at B || ab are required as well as at B || c, for the purpose of the enhancement of a minimum of critical current density Jc in the angular depndence, i.e. the improvement of the Jc anisotropy. In this work, we investigated in detail the flux pinning properties at B || ab for GdBCO coated conductors with splayed CDs produced by heavy-ion irradiations, where the crossing angle i to the ab-plane were controlled. In the range of i = 10, a single Jc peak centered at B || ab appears, which is a similar behaviour to the case of CDs crossing to c-axis: the height of Jc peak reduces and the width becomes broader with increasing the crossing angle. Increasing up to i = 15, on the other hand, two sharp Jc peaks emerge at the two irradiation angles, i.e. triple Jc peaks are formed around B || ab, whereas Jc around B || c remains in a single peak for CD crossing angle up to 30 relative to the c-axis. The difference in the effect of splayed CDs on the Jc behavior between at B || c and at B || ab is attributed to the elliptical nature of the core of flux lines tilted off the c-axis, which induces the difference in the elastic properties of tilted flux lines in an anistropic superconductor.
* This work was performed under the Common-Use Facility Program of JAEA.
|4.||Masashi Mukaida, Iwao Yamaguchi, Ataru Ichinose, Low temperature firing for fluorine free metal organic decomposition films on clad tapes, International Conference on Coated Conductors for Applications (CCA2012), 2012.11.|
|5.||Masashi Mukaida, A. Ichinose, A novel low temperature calcination procedure for fluorine free metal organic decomposition methods, Applied Superconductivity Conference, 2012.10.|
|6.||Kohei Higashikawa, Masayoshi Inoue, K. Imamura, Takanobu Kiss, K. Matsumoto, Y. Yoshida, A. Ichinose, Masashi Mukaida, Investigation of Local Critical Current Density in Fe(Te0.5,Se0.5) Epitaxial Thin-film Superconductors, ICEC24-ICMC2012, 2012.05.|
|7.||Paolo Mele, Kaname Matsumoto, Hiroaki Nagayoshi, Kouhei Fujita, Yutaka Yoshida, Yusuke Ichino, Ataru Ichinose, Takanobu Kiss, Masashi Mukaida, Boris Maiorov, Fedor Balakirev, Scott Baily, Leonardo Civale, Nanostructured Epitaxial Thin Films of Fe-based Superconductors with Enhanced Superconducting Properties, 2012 MRS Spring Meeting, 2012.04.|