Suppression of time reversal symmetry breaking superconductivity in Pr(Os,Ru)_4Sb_12 and (Pr,La)Os_4Sb_12
Lei Shu, W. Higemoto, Y. Aoki, A. D. Hillier, K. Ohishi, K. Ishida, R. Kadono, A. Koda, O. O. Bernal, D. E. MacLaughlin, Y. Tunashima, Y. Yonezawa, S. Sanada, D… 展开作者
Lei Shu, W. Higemoto, Y. Aoki, A. D. Hillier, K. Ohishi, K. Ishida, R. Kadono, A. Koda, O. O. Bernal, D. E. MacLaughlin, Y. Tunashima, Y. Yonezawa, S. Sanada, D. Kikuchi, H. Sato, H. Sugawara, T. U. Ito, M. B. Maple
备注：
4 pages, 4 figures, to appear in Phys. Rev. B (Rapid Communications)
Zero-field muon spin relaxation experiments have been carried out in the Pr(Os_{1-x}Ru_x)_4Sb_12 and Pr_{1-y}La_yOs_4Sb_12 alloy systems to investigate broken time-reversal symmetry (TRS) in the superconducting state, signaled by the onset of a spontaneous static local magnetic field B_s. In both alloy series B_s initially decreases linearly with solute concentration. Ru doping is considerably more efficient than La doping, with a ~50% faster initial decrease. The data suggest that broken TRS is suppressed for Ru concentration x >~ 0.6, but persists for essentially all La concentrations. Our data support a crystal-field excitonic Cooper pairing mechanism for TRS-breaking superconductivity.
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It is pointed out that erroneous Bardeen-Cooper-Schrieffer model equations have been used by Haranath Ghosh in his recent treatment of time-reversal symmetry-breaking superconductivity. Consequently, his numerical results are misleading, and his conclusions are not to the point.
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I review the principal experimental findings about superconductivity, suppression thereof, and related properties of RE_{1-x}Pr_xBa_2Cu3O7 in a decision-tree manner, eliminating the models substantially incompatible with established experimental facts, eventually focussing on the pfσhybridization models and listing on a verbal level the interpretations of the existing experiments as they emerge from such models.
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We have investigated a series of superconducting bridges based on homogeneous amorphous WSi and MoSi films, with bridge widths w ranging from 2 um to 1000 um and film thicknesses d ~ 4-6 nm and 100 nm. Upon decreasing the bridge widths below the respective Pearl lengths, we observe in all cases distinct changes in the characteristics of the resistive transitions to superconductivity. For each of the films, the resistivity curves R(B,T) separate at a well-defined and field-dependent temperature T*(B) with decreasing the temperature, resulting in a dramatic suppression of the resistivity and a s…
