Observation of vortex coalescence, vortex chains and crossing vortices in the anisotropic spin-triplet superconductor Sr2RuO4
✍ Scribed by K. Hasselbach; V.O. Dolocan; P. Lejay; Dominique Mailly
- Publisher
- Elsevier Science
- Year
- 2007
- Tongue
- English
- Weight
- 485 KB
- Volume
- 460-462
- Category
- Article
- ISSN
- 0921-4534
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✦ Synopsis
Scanning lSQUID force microscopy is used to study magnetic flux structures in single crystals of the layered spin-triplet superconductor Sr 2 RuO 4 . Images of the magnetic flux configuration above the ãb -face of the cleaved crystal are acquired, mostly after field-cooling the sample. For low applied magnetic fields, individual vortices are observed, each carrying a single quantum of flux. Above 1 G, coalescence of vortices is discovered. The coalescing vortices may indicate the presence of domains of a chiral order parameter.
When the applied field is tilted from the c-axis, we observe a gradual transition from vortex domains to vortex chains. The in-plane component of the applied magnetic field transforms the vortex domains to vortex chains by aligning them along the field direction.This behavior and the inter-chain distance varies in qualitative agreement with the Ginzburg-Landau theory of anisotropic 3D superconductors. The effective mass anisotropy of Sr 2 RuO 4 , c = 20, is the highest observed in three-dimensional superconductors.
When the applied field is closely in-plane, the vortex form flux channels confined between the crystal-layers. Residual Abrikosov vortices are pinned preferentially on these channels. Thus the in-plane vortices are decorated by crossing Abrikosov vortices: two vortex orientations are apparent simultaneously, one along the layers and the other perpendicular to the layers.