Satoru Okayasu

Enhancement of critical current density in Co-doped BaFe 2 As 2 with columnar defects introduced by heavy-ion irradiation

We report the first realization of columnar defects in Co-doped BaFe

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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Effects of particle irradiations on vortex states in iron-based superconductors

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Giant tunnel magnetoresistance in codeposited fullerene-cobalt films in the low bias-voltage regime

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Design of neutron detector by using a novel superconductor MgB2

single crystals by heavy-iron irradiation. The columnar defects are confirmed by transmission electron microscopy and their density is about 40 % of the irradiation dose. Magneto-optical imaging and bulk magnetization measurements reveal that the critical current density is strongly enhanced in the irradiated region. We also find that vortex creep rates are strongly suppressed by the columnar defects. We compare the effect of heavy-ion irradiation into Co-doped BaFe

Electronic excitation induced sputtering of insulating and semiconducting oxides by high energy heavy ions

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Amorphization behaviors in polycrystalline alumina irradiated with energetic iodine ions

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Irradiation effects on MgB2 bulk samples and formation of columnar defects in high-Tc superconductor

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Superconducting properties of the heavy-ions and neutron irradiated (Cu,C)Ba2Can−1CunO2n+4−δ (n=3, 4 and 5)

and cuprate superconductors.

Enhancement of flux pinning in Bi2Sr2CaCu2O8 by 180 MeV Cu11+ irradiation

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 ...