Preparation of regular arrays of antidots in YBa2Cu3O7 thin films and observation of vortex lattice matching effects

Abstract

Optimized sputtered YBa2Cu3O7 (YBCO) thin films on CeO2-buffered sapphire substrates are patterned into square lattices of submicrometer holes (antidots) with diameters of 250–450 nm and lattice parameters of d=500–1000 nm without deterioration of superconducting properties. In the mixed state, matching effects between the Abrikosov vortex lattice and the artificial antidot lattice are observed. These effects are in the form of peaks or cusps in the critical current density recorded as a function of magnetic induction at integers n and specific rationals k/l of the matching field Bm=(Φ0/d2). The experimental results are discussed in the context of existing theories. The existence of multiquanta vortices confined by the holes in YBCO films are considered.

Commensurability Effects in Superconducting Nb Films with Quasiperiodic Pinning Arrays

“…Recent progress in the fabrication of nanostructures provided the possibility to realize superconducting thin films which contain artificial defects as pinning sites with well-defined size, geometry and spatial arrangement. In particular, artificially produced periodic arrays of submicron holes (antidots) [5,6,7,8] and magnetic dots [9,10,11,12] as pinning sites have been intensively investigated during the last years, to address the fundamental question how vortex pinning -and thus the critical current density j c in superconductors -can be drastically increased.In this context, it has been shown that a very stable vortex configuration, and hence an enhancement of the critical current I c occurs when the vortex lattice is commensurate with the underlying periodic pinning array. This situation occurs in particular at the so-called first matching field B 1 = Φ 0 /A, i.e., when the applied field B corresponds to one flux quantum Φ 0 = h/2e per unit-cell area A of the pinning array.…”

Pinning of Vortices in a Bose-Einstein Condensate by an Optical Lattice

“…Kk, 32.80.Pj Introduction -The effects of a periodic array of pinning centers on vortices in superconducting materials have attracted a lot of experimental [1,2,3,4,5] and theoretical [6,7,8,9,10,11,12,13] attention. Of particular interest is the effect of the pinning potential on the melting of a vortex lattice.…”

The Effects of Pinning on Critical Currents of Superconducting Films

“…By using lithography it is possible to create well-defined periodic nanostructured arrays with well-defined periodic pinning structures in which the microscopic pinning parameters, such as size, depth, periodicity, and density, can be carefully controlled. This enhancement of critical currents using periodic arrays has recently been demonstrated for high T c superconductors [1][2][3][4][5][6][7][8][9][10][11]. Therefore, the study of pinning mechanisms and vortex motion, from both the experimental and theoretical point of view, it is important to understand and to create materials with more applicability.…”