Anomalous field dependence of anisotropy observed in MgB2 single crystals with a torque method

T. Nojima, H. Nagano, A. Ochiai, Hayuyoshi Aoki, B. Kang, S. I. Lee

研究成果: Article査読

4 被引用数 (Scopus)


The field dependence of anisotropy in the mixed state of MgB2 single crystals is studied using torque magnetometry. At all temperatures measured, the anisotropy parameter γ, derived from the angular dependence of magnetic torque τ, increases with increasing field H and shows a plateau with a almost constant value of ∼4.5, indicating that the isotropic π band contribution to the superconductivity weakens with H and only the anisotropic σ band contribution remains in the plateau region. In the low field region below the plateau, we found a change in the functional form of γ(H) at H = H*. In addition, the step-like decrease in the H dependence of d(τ/H)/dH is observed at H*. These anomalies can be related to the change in the vortex lattice structure accompanied by the decrease of the π band contribution.

ジャーナルPhysica C: Superconductivity and its applications
出版ステータスPublished - 2006 10 1

ASJC Scopus subject areas

  • 電子材料、光学材料、および磁性材料
  • 凝縮系物理学
  • エネルギー工学および電力技術
  • 電子工学および電気工学


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