Jung, Soon-Gil Son, Seung-Ku Pham, Duong Kang, Won Nam Lim, Weon Cheol Song, Jonghan Park, Tuson 2024-01-19T20:31:53Z 2024-01-19T20:31:53Z 2021-09-02 2019-03-15 0031-9015 https://pubs.kist.re.kr/handle/201004/120204 We report large improvement of the critical current density (J(c)) of 400-nm-thick MgB2 thin films through carbon (C) ion irradiation. When 350 keV C ions with various dose levels ranging from 1 x 10(13)-1 x 10(15)C atoms/cm(2) are irradiated into the films, the c-axis lattice constant gradually expands with increase in the number of irradiated C ions and superconducting transition temperature (T-c) of the MgB2 films is suppressed. On the other hand, the field performance of J(c) for the MgB2 films remarkably improves after irradiations, which is accompanied by the crossover of the pinning mechanism from weak collective to strong pinning. In addition, scaling behavior of flux pinning force for irradiated MgB2 films shows a dominance of normal point pinning, indicating that the improved field performance of J(c) mainly originates from the point defects, such as vacancies and interstitials, created by C-ion irradiation. Our results suggest that carbon acts as an effective irradiating source as well as a doping source to improve J(c) in high magnetic fields. English PHYSICAL SOC JAPAN SUPERCONDUCTING PROPERTIES NEUTRON-IRRADIATION COLUMNAR DEFECTS VORTEX DYNAMICS YBA2CU3O7-DELTA MAGNETIZATION Enhanced Critical Current Density in the Carbon-Ion Irradiated MgB2 Thin Films Article 10.7566/JPSJ.88.034716 1 JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, v.88, no.3 JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 88 3 scie scopus 000460104400033 2-s2.0-85066755422 Physics, Multidisciplinary Physics Article SUPERCONDUCTING PROPERTIES NEUTRON-IRRADIATION COLUMNAR DEFECTS VORTEX DYNAMICS YBA2CU3O7-DELTA MAGNETIZATION