Effect of high-energy ion irradiation and electron irradiation on textured Bi2Sr2CaCu2Ox—180-MeV Cu11+ and Br11+ irradiations and 3-MeV electron irradiation

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Abstract
180‐MeV Cu11+ and Br11+ irradiations and 3‐MeV electron irradiation were carried out on textured Bi‐2212 tapes and the effects of irradiation on the microstructure and superconducting properties were investigated. Ion irradiation, which creates linear tracks, is very effective in increasing both intragrain Jc and irreversibility field at temperatures below 60 K when field is parallel to the tracks. At 60 K, an order of magnitude higher Birr is obtained for both Cu11+ and Br11+ irradiations. Electron irradiation which creates point defects, on the other hand, is not as effective as ion irradiation except for low temperatures of ∼4.2 K. Apparent pinning potential energy U0 was increased by ion irradiation from ∼15 to ∼40 meV at 41.8 K, while U0 was unchanged by the electron irradiation. However, even U0 of the ion‐irradiated sample is still small. This small U0 increases flux creep at temperatures above 60 K and makes ion irradiation less effective. A small increase of transport Jc was obtained by both ion and electron irradiation for small fluences. However, a significant decrease of transport Jc occurred at fluences which optimize intragrain Jc.