High resolution electron microscopy of heavy-ion induced defects in superconducting Bi-2212 thin films in relation to their effect on Jc

Study of the critical current and irreversibility line of Bi2Sr2CaCu2O8 thin films irradiated with low-energy Co+ and Fe+ ions

“…First, the pinning force of columnar defects sufficiently decreases near the surface [5,6], and the near-surface regions form the whole film with the thickness of about 100 nm or less. Secondly, a set of craters with the diameter exceeding that for the buried columnar defects is formed on the surface of a superconductor during its bombardment with high-energy ions, as it is seen by the transmission electron microscopy [7,8]. Thus, the crystal structure of a near-surface layer appears to be destructed as a result of exposure to the high dose irradiation, required for the formation of the sufficient number of pinning centers.…”

“…Thus, the crystal structure of a near-surface layer appears to be destructed as a result of exposure to the high dose irradiation, required for the formation of the sufficient number of pinning centers. This results in the degradation of critical parameters of a superconductor [7].…”

Interplay of Self-Doping and Disorder in Epitaxial Bi2Sr2Can-1CunO2n+4+x (n=1,2) Thin Films under Heavy-Ion Irradiation

“…Irradiation of semiconducting samples restores metallic superconducting behavior. High energy heavy-ion irradiation (with Pb or U ions, for instance) of high T c superconductors (HTS) produces continuous amorphous tracks [1,2] of 50-120 Å in diameter. This technique is frequently used to create artificial vortex pinning centers [3], as columnar tracks are nonsuperconducting and have a radius comparable to that of vortex core.…”

Point and extended defects in superconductors

“…Since the critical current density J c , is crucially ____________________ important in the applications of HTSCs, huge scientific research have been conducted to optimize J c values. Introducing artificial pinning centers in the HTSCs using several types of energetic radiations was found to be very successful in increasing the vortex pinning forces [3][4][5][6][7][8][9]. Irradiating the HTSCs by heavy ions creates extended structural (columnar) defects in the material.…”