Considerable enhancement of the critical current in a superconducting film by a magnetized magnetic strip

Abstract

We show that a magnetic strip on top of a superconducting strip magnetized in a specified direction may considerably enhance the critical current in the sample. At fixed magnetization of the magnet we observed diode effect -the value of the critical current depends on the direction of the transport current. We explain these effects by a influence of the nonuniform magnetic field induced by the magnet on the current distribution in the superconducting strip. The experiment on a hybrid Nb/Co structure confirmed the predicted variation of the critical current with a changing value of magnetization and direction of the transport current.

Superconducting vortex pinning with artificial magnetic nanostructures

“…In addition to the above-described system, vortex ratchets have been experimentally realized in films with asymmetric arrangements of ''antidots'' [161,162], square arrays of Cu nanotriangles [163], Josephson junctions arrays [164], superconducting constrictions (induced by surface-barrier effects) [165], asymmetric pinning produced with ion irradiation [166], magnetized strips [167] or spacing-graded arrays of pinning centers [168], in asymmetric-shaped mesoscopic superconductors [169], and in films with arrays of magnetic dipoles [170,171]. The phenomenology observed in these systems is very rich.…”

Asymmetric critical current of niobium microbridges with ferromagnetic stripe

“…3-5 Superconductor-ferromagnet ͑SF͒ heterostructures also offer the possibility of improving fundamental material parameters, such as the critical current of superconductors, by controlling the pinning behavior of magnetic vortices. [6][7][8] In addition, SF heterostructures could also find useful application in functional superconducting electronics. Microbridges are particularly suitable systems for such studies due to their simple geometry and ease of fabrication.…”

Transport critical-current density of superconducting films with hysteretic ferromagnetic dots

“…[3][4][5] Another way is to introduce an adequate additional magnetic field that can reduce the local one in superconducting regions. This additional field can be due to the presence of ferromagnetic materials (FMs) that can be located close to the superconductor [6][7][8] or even inside it. [9][10][11][12][13][14][15][16] The introduction of the FMs inside the SCs can also modify the intrinsic pinning and this is known as magnetic pinning.…”