Commensurate and incommensurate vortex states confined in mesoscopic triangles of weak pinning superconducting thin films

ピン止めの弱い超伝導薄膜に閉じこめられた量子磁束状態

小久保 伸人*; 宮原 大*; 岡安 悟  ; 野島 勉*

Kokubo, Nobuhito*; Miyahara, Hajime*; Okayasu, Satoru; Nojima, Tsutomu*

ピン止めの弱いアモルファス超伝導薄膜で作った微少な正三角形、二等辺三角形試料中の量子磁束状態を走査型SQUID顕微鏡で直接観察を行った。量子磁束配列は試料形状の正三角形に整合する三角格子以外に、非整合の準安定状態が得られた。異なる形状の試料で量子磁束配列を解析し、試料形状に対して整合・非整合な配列の対称性と安定性について議論する。

We report on the direct observation of vortex states confined in equilateral and isosceles triangular dots of weak pinning amorphous superconducting thin films with a scanning superconducting quantum interference device microscope. The observed images illustrate not only pieces of a triangular vortex lattice as commensurate vortex states, but also incommensurate vortex states including metastable ones. We comparatively analyze vortex configurations found in different sample geometries and discuss the symmetry and stability of commensurate and incommensurate vortex configurations against deformations of the sample shape.