Jan Koláček

The ac effect of vortex pinning in the arrays of defect sites on Nb films

Niobium thin films with spacing-graded array of submicrometer-scaled holes had been fabricated using electron beam lithography through a lift-off technique. The magnetoresistance measurements and current-voltage characteristics were carried out with the external magnetic field applied perpendicular to the film plane, in which commensurable effects were observed in both experiments. The magnetoresistance with positive/negative directions of dc current revealed identical curves except the dips at matching fields separated. Two distinct current-voltage curves, which resulted from the positive and negative applied current directions, respectively, were discerned when the external magnetic field was fixed at the matching field, which is believed to be due to asymmetry pinning potential in the spacing-graded array of holes. In addition, ac current-voltage curve measured at matching field showed a ratchet bump along with another extra peak associated with incommensurable effect.

Nuclear resonance shift in the vortex lattice in YBa2Cu3O7

The NMR and NQR spectra of

Vortex ratchet effect in a niobium film with spacing-graded density of pinning sites

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Surface charge of a flat superconducting slab in the Meissner state

Cu in the CuO

Experimental and simulation study of missing matching peaks in Nb thin films with square pinning arrays

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ELECTROSTATIC FIELD IN SUPERCONDUCTORS I: OPEN QUESTIONS

plane of YBa

Thermopower in superconductors : Temperature dependence of magnetic flux in a bimetallic loop

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Electric field in stationary superconductors

Cu

ELECTROSTATIC FIELD IN SUPERCONDUCTORS AT EQUILIBRIUM

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ELECTROSTATIC FIELD IN SUPERCONDUCTORS II: BALANCE OF FORCES

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