異方的超伝導体における上部臨界磁場と次元性の相関

URI http://harp.lib.hiroshima-u.ac.jp/it-hiroshima/metadata/12290
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Title
異方的超伝導体における上部臨界磁場と次元性の相関
Title Alternative
Correlation between upper critical field and dimensionality in an unconventional superconductor
Author
氏名 安塚 周磨
ヨミ ヤスズカ シュウマ
別名 Yasuzuka Syuma
Subject
organic conductor
upper critical field
dimensionality
spin fluctuations
pairing symmetry
Abstract

β-(BDA-TTP)2SbF6 is a layered organic superconductor with relatively high transition temperature Tc of 7.5 K. In order to investigate the superconducting(SC) state of β-(BDA-TTP)2SbF6, its interlayer resistance has been measured at magnetic fields up to 15 T and temperatures down to 1.5 K. The upper critical fields(Hc2) parallel and perpendicular to the conduction layer are determined and dimensional crossover from anisotropic three-dimensional(3D) behavior to 2D behavior is found around 6 K. When a magnetic field is rotated within the conduction layer at 6 K, Hc2 for magnetic field along the a* + c* direction is slightly larger than that for along the a* - c* direction. Normal-state magnetoresistance has the same symmetry as Hc2 and shows maximum(minimum) when a magnetic field is applied parallel to the a* - c*(a* + c*) direction. This behavior can be explained in terms of a Fermi surface anisotropy. At 3.5 K, however, we find clear fourfold symmetry of Hc2 despite the normal-state magnetoresistance shows twofold symmetry arising from the Fermi surface anisotropy. Origin of fourfold symmetry of Hc2 is discussed in terms of SC gap structure in β-(BDA-TTP)2SbF6.

Journal Title
広島工業大学紀要. 研究編
Volume
53
Spage
181
Epage
184
Published Date
2019-02
Publisher
広島工業大学
ISSN
1346-9975
NCID
AA11599110
Language
jpn
NIIType
Departmental Bulletin Paper
Text Version
出版社版
Rights
publisher
Set
it-hiroshima