共查询到20条相似文献,搜索用时 15 毫秒
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H. Maletta M. Weber P. Birrer F. N. Gygax B. Hitti E. Lippelt A. Schenck 《Hyperfine Interactions》1990,61(1-4):1121-1123
Transverse field μSR studies of the system ErBa2Cu3Ox with x=6.4, 6.53 and 7 reveal a split signal with each component displaying a distinct paramagnetic or Knight shift related
to the Er 4f-moments. This implies the presence of transferred hyperfine fields even in the superconducting state. 相似文献
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H. Maletta P. Birrer F. N. Gygax B. Hitti E. Lippelt A. Schenck M. Weber 《Hyperfine Interactions》1991,63(1-4):235-240
Results from zero-field μSR experiments are presented, performed on the high-T
c compounds ErBa2Cu3Ox for various oxygen contentx with 6≤x≤7 at temperatures between 40 mK and 300 K. The aim was to study the magnetic ordering behavior of the Cu moments and the
Er moments, and its interplay with superconductivity. 相似文献
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The interfaces in ramp-type YBa2Cu3Ox/PrBa2Cu3Ox/YBa2Cu3Ox Josephson junctions with different ramp slopes were characterized electrically and structurally. From the cross-sectional TEM images, it has been found that the epitaxy remains through all layers even on the ramp surface, providing the ramp angle is less than 45°. No big defects such as grain boundaries and secondary phases occurred at the interface. The major defects which appeared at the interface are antiphase boundaries which were formed by lattice shifts with c/3 unit between PrBa2Cu3Ox and YBa2Cu3Ox. The interface between YBa2Cu3Ox base-layer and PrBa2Cu3Ox barrier is more defective in comparison with that between PrBa2Cu3Ox barrier and top-layer. Alteration of the ramp slope from 10° to 45° leads to a significant increase in the density of defects near the base-YBa2Cu3Ox/PrBa2Cu3Ox interface. The average roughness of the ramp surface created by ion milling is about 10 nm, which seems insensitive to the ramp slope. The damaged ramp surface could be repaired during the subsequent deposition process, leading to a negligible interface resistance. 相似文献
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C. Stockinger W. Markowitsch W. Lang W. Kula R. Sobolewski 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,2(3):301-311
We report our studies on the superconducting and normal-state properties of metallic thin films ( 52 K) exposed to long-term white-light illumination (photodoping). It was observed that the effects of photoexcitation strongly
depended on the temperature at which the photodoping was performed. At low temperatures, both the Hall mobility and the Hall
number were photoenhanced, whereas, at temperatures slightly below room temperature, the Hall mobility initially showed an
abrupt increase followed by a long-term decrease, and the Hall number increased even stronger than at low temperatures. The
enhancement of the film's superconducting transition temperature Tc, caused by photodoping, exhibited the same temperature dependence as the enhancement of the Hall number, being largest ( 2.6 K) at high temperatures. From the asynchronous behavior of the Hall quantities, we conclude that both the photoassisted
oxygen ordering and charge transfer mechanisms contribute to photodoping. The relative contributions of both mechanisms and,
thus, the electronic properties of the photoexcited state are strongly temperature dependent. Studies of the relaxation of
the photoexcited state at 290 K showed an unexpectedly short relaxation time of the Hall mobility after termination of the
illumination. The relaxation saturated somewhat below the initial, undoped value, similarly to the decrease of the Hall mobility,
observed upon long illumination. These latter findings give evidence for a competition between the oxygen ordering and thermal
disordering processes during and after the photoexcitation in the high-temperature range.
Received: 13 October 1997 / Accepted: 19 November 1997 相似文献
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《Physics letters. A》1987,121(6):305-306
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Zhao Min-Guan Zhao Xiao-Ning Zheng Xiao-Lan 《Zeitschrift für Physik B Condensed Matter》1988,73(1):1-3
Onset transition temperature (123±1) K was observed in the BiCaSrCu2Ox bulk materials prepared by means of conventional ceramic technique. The resistance and AC susceptibility measurements show that there are two highT
c
phases. EPR measurement shows that belowT
c
(R=0), an intense line at zero field was observed. It is either associated with the glass feature or the spin triplet transition of Cu2+–Cu2+ pair via exchange interaction.The Project Supported by National Natural Science Foundation of China 相似文献
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Angular dependences of the magnetization hysteresis loops have been studied at T=77 K on YBCO single crystals exhibiting the peak effect. The peak effect is shown to be related to the pinning of longitudinal
vortices along the c axis at twin boundary-type ordered defects. The behavior of the peak effect at intermediate angles is explained by anisotropic
magnetic field penetration into quasi-two-dimensional superconductors. In thin crystals with a dilute ordered-defect structure
this can result in an enhanced peak effect due to formation of a vortex kink structure and to “internal” pinning of transverse
vortex segments at Cu-O sheets.
Fiz. Tverd. Tela (St. Petersburg) 39, 425–431 (March 1997) 相似文献