Flux pinning inYaBa2Cu3O

Abstract

Ordered arrays of columnar defects have been fabricated by direct electron-beam writing on c Ќ -oriented YBa 2 Cu 3 O 7Ϫ␦ ͑YBCO͒ thin films. Serving as strong pinning sites, columnar defects cause a 70% enhancement of critical current density J c at Tϭ77 K in magnetic fields parallel to the c axis. The matching effect of the pinning force density has been observed, due to commensurability between flux lines and arrays of columnar defects. The pinning strength of columnar defects has been compared with that of point defects, and found to be greater than the latter in YBCO films. These results suggest that this way of pinning center fabrication could be a promising tool in studies of the pinning mechanism in high-temperature superconductors.

Superconducting vortex pinning with artificial magnetic nanostructures

“…Pinning effects by ordered arrays of defects have been intensively studied for several decades; first, with defects of lateral size in the micron range, like arrays of holes [9], holes in superconducting networks [10], or magnetic particles [11,12]. More recently, the development of new lithography techniques has allowed the reduction of the size, using submicron defects such as arrays of holes [13] or spatially modulated e-beam irradiation damage with electron [14] or ion beams [15].…”

Three-dimensional Ginzburg-Landau simulation of a vortex line displaced by a zigzag of pinning spheres

“…For this reason artificially made pinning centers are useful and many kinds have been fabricated 13,14,15,16,17 though not of the kind considered here. In this paper the Ginzburg-Landau theory was numerically solved ona threedimensional mesh to study properties of a vortex line near a zigzag of pinning centers.…”

Rectification and phase locking of graphite

“…The properties of Shapiro steps [1,2] have been studied experimentally and theoretically for many years in the dissipative dynamics of many-body systems, such as charge-density or spin-density wave conductors [3][4][5][6][7], vortex lattices [8][9][10][11][12][13], colloids [14,15] and Josephsonjunction arrays (JJA) biased by external currents [16][17][18][19][20]. To understand these very complex physical systems, the focus was always on simple many-body models.…”