Point and extended defects in superconductors

Abstract

The effect of point defects created by γ-irradiation and extended defects created by Pb-ion irradiation on the behavior of the critical current density, J c in several superconductors have been investigated. We have found a limitation of the role of both types of defects on enhancing J c . We report an explanation of the effect of γ-irradiation and Pb-ion irradiation doses on J c in these materials. The explanation is based on combining several competing mechanisms of irradiation which we believe to take place mainly in the regions of the grain boundaries. The influences of these mechanisms were found to vary with the irradiation dose level.

Applications of YBCO-coated conductors: a focus on the chemical solution deposition method

“…Introducing artificial pinning centers in the HTSCs using several types of energetic radiation was found to be very successful at increasing the vortex pinning forces. [11][12][13][14][15][16][17][18][19][20] Irradiating the HTSCs with heavy ions 12,13,20 creates extended structural (columnar) defects in the material. Because the columnar defects can pin a vortex along its whole length, they are considered to be effective vortex pinning sites (even at high temperatures).…”

Enhancing the pinning strengths in polycrystalline MgB2

“…This indicates that as the temperature increases, the effect of γ-irradiation on J c becomes less significant. This limiting effect of γ-irradiation dose on the critical current density has been reported also for several HTSCs irradiated by heavy ions and by γ-rays [11][12][13][14]. Fig.…”

The influence of Pb‐ion irradiation on melt‐textured YBa2Cu3Ox crystals

“…Although the further increase of Pb-ion irradiation dose enhanced the pinning strength values, compared to those in the non-irradiated sample, it could not produce further enhancement of the pinning strengths after the initial dose increase. These results clearly signify the limiting role of the dose of heavy-ion irradiation on enhancing the pinning strength in these samples [15].…”

“…The enhancement of pinning strengths at ion irradiation dose of B Φ = 0.5 T and their suppression at the higher dose of B Φ = 2 T can be explained to be due to a combination of competing two factors [15]. The first factor is the enhancing factor of ion irradiation at low doses.…”