Anisotropic flux penetration into Nb square superconducting networks

Tsuchiya, Yuji; Nakajima, Yasuyuki; Tamegai, T.; Nagasawa, Shuichi; Hidaka, Mutsuo

doi:10.1088/0953-2048/27/5/055008

Cited by 6 publications

(1 citation statement)

References 32 publications

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“…In type-II superconducting films anisotropy often causes a preferred direction for motion of the vortices present in the material [1,2]. The anisotropic behavior can have many different origins, e.g., the presence of material microstructures such as twin and anti-phase boundaries [3,4], planar microdefects [5], misoriented substrates [6,7], asymmetric pinning potentials [8], columnar defects [9,10], and patterned arrays of holes [11]. In all these cases the anisotropy is due to permanent characteristics of the sample.…”

Section: Introductionmentioning

confidence: 99%

Active control of thermomagnetic avalanches in superconducting Nb films with tunable anisotropy

Carmo

Colauto

Andrade

et al. 2018

Supercond. Sci. Technol.

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Active triggering and manipulation of ultrafast flux dynamics in superconductors are demonstrated in films of Nb. Controlled amounts of magnetic flux were injected from a point along the edge of a square sample, which at 2.5 K responds by nucleation of a thermomagnetic avalanche. Magneto-optical imaging was used to show that when such films are cooled in the presence of in-plane magnetic fields they become anisotropic, and the morphology of the avalanches change systematically, both with the direction and magnitude of the field. The images reveal that the avalanching dendrites consistently bend towards the direction perpendicular to that of the in-plane field. The effect increases with the field magnitude, and at 1.5 kOe the triggered avalanche becomes quenched at the nucleation stage. The experimental results are explained based on a theoretical model for thermomagnetic avalanche nucleation in superconducting films, and by assuming that the frozenin flux generates in-plane anisotropy in the film thermal conductance. The results demonstrate that applying in-plane magnetic fields to film superconductors can be a versatile external tool for controlling their ultrafast flux dynamics.

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