Direct Imaging of Vortex Polygons and Vortex Shells in Mesoscopic Squares of a Weak Pinning Superconducting Thin Film

Vortex shells in mesoscopic triangles of amorphous superconducting thin films

“…The corresponding packing sequence reveals that the single shell structure is stably reformed after the formation of the double shell structure. Thus, closed shell configurations are not uniquely defined, in contrast to the results in mesoscopic circle and square dots [7,12]. We believe that the observed feature is not related to the metastability, but intrinsic to mesoscopic triangle dots.…”

“…As seen from Fig. 2(b), in the square dots, the occupation N 1 in the first shell varies from 1 to 4 for L = 1-4, and this repeats for L = 5-16 [12]. In the circle dots [ Fig.…”

“…In this study, we extend the previous work not only to study vortex states in equilateral triangle dots for L more than 11 (up to 15), but also to understand whether vortex arrangements can be interpreted in terms of vortex shells, as seen in circle and square dots [7,12].…”

“…The vortex images presented in this study were taken on equilibrium vortex states prepared by the field-cool procedure, in which the magnetic field was applied in some temperatures (∼ 15 K) above T c , followed by cooling the samples in the magnetic field to temperatures of 3-4 K (< T c ) for imaging [7]. 3,12). Here, we employ the Many metastable states are created by the incommensurability between the geometry and vorticity: At L = 7, a single shell of (7) appears [ Figs.…”

Commensurate and Incommensurate Vortex States Confined in Mesoscopic Triangles of Weak Pinning Superconducting Thin Films

“…The interplay between the intervortex interaction and the confinement results in unique vortex states with strong features of the sample shape, different from the Abrikosov-triangular lattice in bulk superconductors. 8 It is well established that in mesoscopic disks, vortices form circular symmetric shells and obey the specific rules for shell filling with increasing the vorticity L. 9,10 Meanwhile, in other geometric shapes such as squares [11][12][13] and pentagons, 14 the formation of vortex shells is not well defined as in disks owing to the commensurability between the geometry and the vortex arrangement. In mesoscopic triangles, which we focus on this study, vortices form intrinsically a piece of the triangular lattice since they match the geometric shape with threefold * E-mail: kokubo@pc.uec.ac.jp DRAFT axial symmetry.…”