Reinforcement of pinning by surface magnetic microparticles in high-Tc superconductors

Abstract

A reinforcement of pinning in high-Tc superconducting materials by surface magnetic microparticles obtained by ion implantation is observed. Measurements are made by the method of magnetically modulated microwave absorption. In single crystals of Bi2Sr2CaCu2O8 an ensemble of magnetic particles is formed directly in a subsurface layer of the superconductor by the implantation of Fe+ ions followed by annealing. In experiments with YBa2Cu3O7 the magnetic microparticles of iron were formed individually in SiO2 films which were then applied to the surface of a thin film of YBa2Cu3O7, and measurements were made on the composite structure. In both cases reinforcement of the pinning is observed. In the limits of the chosen implantation regimes the pinning effect becomes stronger with increasing fluence of implanted iron atoms.

Observation of Pinning Strengthening in “MgB₂ – CNT – α-Fe” Nanocomposites Studied by Microwave Absorption Technique

“…Small particles with diameter less 10 -6 cm is composed of a single magnetic domain [4] and have larger magnetic moment in contrast to multi-domain large magnetic particles in magnetic field range up to saturation value. Bat particles with larger magnetic moment more strongly attract vortex lines and act as more efficient pinning centers [5].…”

Properties and Types of Superconductors

“…Further studies are still required to study flux pinning and various mechanisms for classifications in superconducting materials. Few other investigations are considered by substitution of magnetic nanoparticles to illustrate normal-like deficiencies in superconducting matrix, interrelate with the vortices and behave as useful pinning centers inside the high temperature superconductors Bi-2223 materials [113,126,127].…”

Fabrication of Bi₂Sr₂Ca_n-1Cu_nO_y / Al₂O₃-Particles on MgO Films by rf Magnetron Sputtering Method

“…Generally, impurities in superconductors are expected as a pinning center, which was Au + , Pb and Fe was reported in superconducting thin films. [2][3][4][5] However, there are few reports on the pinning center in Bi-based superconductor, which is useful at 77K.…”