Dominant factors for the pinning enhancement by large artificial partial and complete antidots in superconducting films

Abstract

Partially (blind) or fully perforated antidots (BADs or ADs, respectively) fabricated by laser lithography and ion beam etching in superconducting YBa 2 Cu 3 O 7 (YBCO) films possess a cumulative circumference wall surface, which is found to be responsible for pinning vortices and/or magnetic flux, whereby increasing the critical current density (J c ) relative to corresponding plain (unpatterned) films. Using a variety of contrastingly shaped, relatively large 2-5 μm BADs and ADs, the J c of YBCO thin films has been effectively increased within the relatively narrow band of wall surfaces of antidots, independent whether patterns are AD or BAD type. Independence of antidot types indicates that enhancement is insensitive whether magnetic flux is inside the ADs, or vortices are inside the BADs. Within this AD wall surface band region a clear shape dependence also emerges. This finding may also provide a guide for superconducting devices requiring maximal J c and reduced associated vortex movement noise.

Critical current of a layered high-temperature superconductor with artificial pinning centers: the Monte Carlo simulation

“…Another type of pinning centers are the extended defects-areas with partially suppressed superconductivity or holes (antidots) with radii from several hundreds of nanometers to several micrometers. Such defects can be created by means of ion etching [22][23][24] and are usually arranged in periodic lattices. In [22,23], a square lattice of holes spaced by 300 nm was studied.…”

“…In [22,23], a square lattice of holes spaced by 300 nm was studied. In [24], the hole size was about several microns. Creating such defects provided significant increase in the critical current.…”

The influence of BaSnO3 and BaZrO3 nanoinclusions on the critical current and local structure of HTS coated conductors

“…These compounds are used to fabricate composite superconducting materials-HTSC tapes of the second generation and wires based on them [1][2][3]. The critical current J c , which is the most important practical characteristic of a superconductor, as well as the dependence of the critical current on the applied magnetic field J c (H), can be improved by adding the artificial pinning centers using various methods, for example, introducing the multilayered structure [4], irradiating by heavy ions [5] or fabricating a pattern of microholes [6], magnetic dot arrays [7], etc. One of such methods is the introduction of non-superconducting nanoinclusions into the superconducting matrix, which under certain conditions can play the role of additional artificial pinning centers and lead to an increase in the critical current [8][9][10].…”