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Tamegai, Tsuyoshi*; Taen, Toshihiro*; Yagyuda, Hidenori*; Tsuchiya, Yuji*; Mohan, S.*; Taniguchi, Tomotaka*; Nakajima, Yasuyuki*; Okayasu, Satoru; Sasase, Masato*; Kitamura, Hisashi*; et al.
Superconductor Science and Technology, 25(8), p.084008_1 - 084008_14, 2012/08
Times Cited Count:85 Percentile:93.2(Physics, Applied)Various kinds of energetic particles are irradiated into iron-based superconductors, and their effects on the critical current density and vortex dynamics have been systematically studied. It is found that is enhanced and vortex dynamics is strongly suppressed by energetic particles having a sufficient energy deposition rate, similar to the case of high temperature cuprate superconductors. The enhancement of , in general, persists up to much higher irradiation doses than in cuprates. However, details of the effect of irradiation depend on the kind of ion species and their energies. Even with the same ions and energies, the effect is not universal for different kinds of iron-based superconductors. The correlated nature of defects created by heavy-ion irradiation is confirmed by the angular dependence of irreversible magnetization.
Tamegai, Tsuyoshi*; Taen, Toshihiro*; Yagyuda, Hidenori*; Nakajima, Yasuyuki*; Okayasu, Satoru; Sasase, Masato*; Kitamura, Hisashi*; Murakami, Takeshi*; Kambara, Tadashi*; Kanai, Yasuyuki*
Physica C, 471, p.777 - 780, 2011/00
Times Cited Count:6 Percentile:29.25(Physics, Applied)Magnetic relaxations in Ba(FeCo)As before and after swift particle irradiations are measured. The normalized relaxation rate S shows a clear suppression in a pristine sample at low fields below the self-field. Heavy-ion irradiations suppress these anomalies considerably, although there still remain weak features depending on ion species and/or energies. In a proton irradiated sample, the low-field anomaly of S survives although it is smeared compared with that in a pristine sample. All these results indicate that the low-field anomaly of S is suppressed by defects, and correlated defects have stronger effects.
Ono, Fumihisa*; Chimi, Yasuhiro; Ishikawa, Norito; Kanamitsu, Hiroaki*; Matsushima, Yasushi*; Iwase, Akihiro*; Kambara, Tadashi*
Nuclear Instruments and Methods in Physics Research B, 257(1-2), p.402 - 405, 2007/04
Times Cited Count:5 Percentile:40.96(Instruments & Instrumentation)no abstracts in English
Chimi, Yasuhiro; Iwase, Akihiro*; Ishikawa, Norito; Kobiyama, Mamoru*; Inami, Takashi*; Kambara, Tadashi*; Okuda, Shigeo*
Nuclear Instruments and Methods in Physics Research B, 245(1), p.171 - 175, 2006/04
Times Cited Count:16 Percentile:72.85(Instruments & Instrumentation)We have studied effects of irradiation with energetic particles on defect accumulation in nanocrystalline gold (nano-Au). The specimens of nano-Au foil (3-5 m thickness) with various grain sizes (23-156 nm) are prepared by the gas deposition method and subsequent thermal annealings. Irradiations of the specimens with 60-MeV C ions, 3.54-GeV Xe ions or 2.0-MeV electrons are performed at low temperature. The defect accumulation behavior is observed by measuring the electrical resistivity change during irradiation. Through an analysis of defect accumulation behavior, cross-sections for defect production, , and annihilation, , in nano-Au increase monotonically as the grain size decreases. These results are considered to be caused by the existence of a large volume fraction of the regions near grain boundaries in nano-Au where the threshold energy for atomic displacements, E, becomes lower than in polycrystalline gold. The possibility of electronic excitation effects in nano-Au is also discussed.
Ono, Fumihisa*; Kanamitsu, Hiroaki*; Matsushima, Yasushi*; Chimi, Yasuhiro; Ishikawa, Norito; Kambara, Tadashi*; Iwase, Akihiro*
Nuclear Instruments and Methods in Physics Research B, 245(1), p.166 - 170, 2006/04
Times Cited Count:4 Percentile:34.39(Instruments & Instrumentation)Specimens of both ordered and disordered Fe-28.3at.%Pt alloys were irradiated with 200-MeV Xe ions to the fluence of 10 ions/cm. Measurements of AC-susceptibility-temperature curves were made for each specimen before and after the irradiation by using a specially designed apparatus for rapid measurements. In contrast to the expectation from the previous results for Fe-Ni alloys, in disordered Fe-Pt invar alloy the Curie temperature, T decreased about 15 K by the irradiation. This fact cannot be explained by considering the lattice expansion effect alone. In Fe-Pt invar alloys the effect of lattice expansion may be cancelled out by some other effects which may be originated from the large difference in atomic mass between the two elements. For ordered Fe-Pt alloy, T decreased as large as 60 K with the same fluence. The value of T for both ordered and disordered Fe-Pt invar alloys coincide with each other after the irradiation. This fact can be explained by considering that the ordered state becomes disordered by the irradiation.
Matsushima, Yasushi*; Sun, N. Q.*; Kanamitsu, Hiroaki*; Matsushita, Masafumi*; Iwase, Akihiro*; Chimi, Yasuhiro; Ishikawa, Norito; Kambara, Tadashi*; Ono, Fumihisa*
Journal of Magnetism and Magnetic Materials, 298(1), p.14 - 18, 2006/03
Times Cited Count:8 Percentile:38.44(Materials Science, Multidisciplinary)Pressure dependence of the irradiation-induced ferromagnetism recently found in Fe-Ni invar alloys was investigated under hydrostatic pressures up to 7.5 GPa. A rectangular sheet of Fe-30.2at% Ni invar alloy was irradiated with 80-MeV Xe ions. The range was much smaller than the thickness of the sample. The Curie temperature of the irradiated part increased by 63 K, and the absolute value of the pressure coefficient, d/d was smaller than that of non-irradiated part. The relation ( - ) holds with n = 2 for both non-irradiated and irradiated part. The itinerant character was not so much modified by irradiation.
Iwase, Akihiro; Hamatani, Yutaro*; Mukumoto, Yoshinori*; Ishikawa, Norito; Chimi, Yasuhiro; Kambara, Tadashi*; Mller, C.*; Neumann, R.*; Ono, Fumihisa*
Nuclear Instruments and Methods in Physics Research B, 209(1-4), p.323 - 328, 2003/08
Times Cited Count:20 Percentile:77.2(Instruments & Instrumentation)Fe=Ni Invar alloy is irradiated with GeV Xe and U ions at room temperature. By the irradiation, the Curie temperature of the soecimens increases, which is correlated with the electronic stopping power. This phenomenon can be explained as due to the lattice expansion and/or the local increase in Ni concentration.
Iwase, Akihiro; Hasegawa, Tadayuki*; Chimi, Yasuhiro; Tobita, Toru; Ishikawa, Norito; Suzuki, Masahide; Kambara, Tadashi*; Ishino, Shiori*
Nuclear Instruments and Methods in Physics Research B, 195(3-4), p.309 - 314, 2002/10
Times Cited Count:12 Percentile:60.82(Instruments & Instrumentation)no abstracts in English
Okayasu, Satoru; Sasase, Masato; Hojo, Kiichi; Chimi, Yasuhiro; Iwase, Akihiro; Ikeda, Hiroshi*; Yoshizaki, Ryozo*; Kambara, Tadashi*; Sato, H.*; Hamatani, Yutaro*; et al.
Physica C, 382(1), p.104 - 107, 2002/10
Times Cited Count:28 Percentile:75.41(Physics, Applied)no abstracts in English
Chimi, Yasuhiro; Iwase, Akihiro; Ishikawa, Norito; Kambara, Tadashi*
Nuclear Instruments and Methods in Physics Research B, 193(1-4), p.248 - 252, 2002/06
Times Cited Count:2 Percentile:18.93(Instruments & Instrumentation)no abstracts in English
Ishikawa, Norito; Iwase, Akihiro; Chimi, Yasuhiro; Michikami, Osamu*; Wakana, Hironori*; Hashimoto, Takeo*; Kambara, Tadashi*; Mller, C.*; Neumann, R.*
Nuclear Instruments and Methods in Physics Research B, 193(1-4), p.278 - 282, 2002/06
Times Cited Count:8 Percentile:47.9(Instruments & Instrumentation)Swift heavy ions with wide energy range of 80MeV-3.84GeV have been irradiated to EuBaCuO oxide superconductors, and the lattice parameter change due to elecronic excitation has been measured. In the high ion-velocity region, the change in lattice parameter per unit fluence varies as the 4th power of the electronic stopping power. However, in the low-velocity region, the deviation from the 4th power dependence is observed. The results are analyzed by using the primary ionization rate, and it is found that the results support that the Coulomb explosion triggers the atomic displacements.
Okayasu, Satoru; Sasase, Masato; Kuroda, N.; Iwase, Akihiro; Kazumata, Yukio*; Kambara, Tadashi*
Physica C, 357-360(Part.1), p.501 - 504, 2001/09
no abstracts in English
Kuroda, N.; Ishikawa, Norito; Chimi, Yasuhiro; Iwase, Akihiro; Ikeda, Hiroshi*; Yoshizaki, Ryozo*; Kambara, Tadashi*
Physical Review B, 63(22), p.224502_1 - 224502_5, 2001/06
Times Cited Count:9 Percentile:48.04(Materials Science, Multidisciplinary)no abstracts in English
Ishikawa, Norito; Iwase, Akihiro; Chimi, Yasuhiro; Michikami, Osamu*; Wakana, Hironori*; Kambara, Tadashi*
Journal of the Physical Society of Japan, 69(11), p.3563 - 3575, 2000/11
Times Cited Count:9 Percentile:52.88(Physics, Multidisciplinary)no abstracts in English
Chimi, Yasuhiro; Iwase, Akihiro; Ishikawa, Norito; Kuroda, N.; Kambara, Tadashi*
Nuclear Instruments and Methods in Physics Research B, 164-165, p.408 - 414, 2000/04
Times Cited Count:7 Percentile:47.27(Instruments & Instrumentation)no abstracts in English
Okayasu, Satoru; Kuroda, N.*; Iwase, Akihiro; Kambara, Tadashi*
Advances in Superconductivity XI, p.287 - 290, 1999/00
no abstracts in English
Ishikawa, Norito; Chimi, Yasuhiro; Kuroda, N.*; Iwase, Akihiro; Kambara, Tadashi*
Phys. Scr., T80(B), p.559 - 561, 1999/00
Times Cited Count:3 Percentile:33.44(Physics, Multidisciplinary)no abstracts in English
Kuroda, N.; Ishikawa, Norito; Chimi, Yasuhiro; Iwase, Akihiro; Okayasu, Satoru; Ikeda, Hiroshi*; Yoshizaki, Ryozo*; Kambara, Tadashi*
Physica C, 321(3-4), p.143 - 150, 1999/00
Times Cited Count:11 Percentile:54.6(Physics, Applied)no abstracts in English
Ishikawa, Norito; Chimi, Yasuhiro; Iwase, Akihiro; Maeta, Hiroshi; *; Michikami, Osamu*; Kambara, Tadashi*; *; *; Terasawa, M.*
Nuclear Instruments and Methods in Physics Research B, 135, p.184 - 189, 1998/00
Times Cited Count:15 Percentile:73.06(Instruments & Instrumentation)no abstracts in English
Iwase, Akihiro; Ishikawa, Norito; Chimi, Yasuhiro; Wakana, Hironori*; Michikami, Osamu*; Kambara, Tadashi*; *
Nuclear Instruments and Methods in Physics Research B, 146(1-4), p.557 - 564, 1998/00
Times Cited Count:20 Percentile:80.42(Instruments & Instrumentation)no abstracts in English