共查询到20条相似文献,搜索用时 15 毫秒
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Egetenmeyer N Gavilano JL Maisuradze A Gerber S MacLaughlin DE Seyfarth G Andreica D Desilets-Benoit A Bianchi AD Baines Ch Khasanov R Fisk Z Kenzelmann M 《Physical review letters》2012,108(17):177204
We report on muon spin rotation studies of the noncentrosymmetric heavy fermion antiferromagnet CeRhSi3. A drastic and monotonic suppression of the internal fields, at the lowest measured temperature, was observed upon an increase of external pressure. Our data suggest that the ordered moments are gradually quenched with increasing pressure, in a manner different from the pressure dependence of the Néel temperature. At 23.6 kbar, the ordered magnetic moments are fully suppressed via a second-order phase transition, and T(N) is zero. Thus, we directly observed the quantum critical point at 23.6 kbar hidden inside the superconducting phase of CeRhSi3. 相似文献
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The upper critical field in a model with dispersion in the f-band of a periodic Anderson model has been calculated. 相似文献
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The upper critical field Hc2 (T) and its temperature derivative at Tc in the heavy fermion superconductors have been calculated by using the simplified Kondo lattice model. 相似文献
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We have derived the so-called gap equation, which determines the upper critical magnetic field, perpendicular to conducting chains of a quasi-one-dimensional superconductor. By analyzing this equation at low temperatures, we have found that the calculated angular dependence of the upper critical magnetic field is qualitatively different than that in the so-called effective mass model. In particular, our theory predicts a non-analytical angular dependence of the upper critical magnetic field, H c2(0) − H c2(α) ∼ α3/2, when magnetic field is close to some special crystallographic axis and makes an angle α with it. We discuss possible experiments on the superconductor (DMET)2I3 to discover this non-analytical dependence. 相似文献
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K. Elboussiri 《Applied Physics A: Materials Science & Processing》1994,59(2):223-224
We were able to observe a certain type of defects in the heavy fermion superconductor UPt3, using electron microscopy in the dark-field imaging mode. We have identified this type of defects as discommensurations since the high-resolution transmission electron microscope shows a translational shift across the wall of these discommensurations. 相似文献
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Bauer E Hilscher G Michor H Paul Ch Scheidt EW Gribanov A Seropegin Y Noël H Sigrist M Rogl P 《Physical review letters》2004,92(2):027003
CePt3Si is a novel heavy fermion superconductor, crystallizing in the CePt3B structure as a tetragonally distorted low symmetry variant of the AuCu3 structure type. CePt3Si exhibits antiferromagnetic order at T(N) approximately 2.2 K and enters into a heavy fermion superconducting state at T(c) approximately 0.75 K. Large values of H(')(c2) approximately -8.5 T/K and H(c2)(0) approximately 5 T refer to heavy quasiparticles forming Cooper pairs. Hitherto, CePt3Si is the first heavy fermion superconductor without a center of symmetry. 相似文献
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We report upper critical field B(c2)(T) measurements on a single-crystalline sample of the ferromagnetic superconductor UCoGe. B(c2)(0) obtained for fields applied along the orthorhombic axes exceeds the Pauli limit for B parallela,b and shows a strong anisotropy B(c2)(a) approximately B(c2)(b)>B(c2)(c). This provides evidence for an equal-spin pairing state and a superconducting gap function of axial symmetry with point nodes along the c axis, which is also the direction of the uniaxial ferromagnetic moment m(0)=0.07micro(B). An unusual curvature or kink is observed in the temperature variation of B(c2) which possibly indicates UCoGe is a two-band ferromagnetic superconductor. 相似文献
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采用二带Ginziburg-Landau(G-L)理论模型计算了各向异性超导体的上临界磁场,发现上临界磁场Hc2的解析式中包含序参量的各向异性和有效质量的各向异性;上临界磁场ab-面内分量Hc|2|ab、c-轴方向分量Hc|2|ab与实验数据符合;上临界磁场比率在实验许可范围之内。 相似文献
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《Physics letters. A》1999,260(5):424-428
The relative change of the microwave surface resistance has been measured as a function of temperature in the superconducting and normal states of UPt3 using a cavity perturbation technique. With our frequency range of ∼9–38 GHz, the microwave photon energy (ℏω) is ∼20–95% of the estimated zero-temperature (BCS) energy gap (2Δ0) of UPt3. The surface resistance shows a change in slope as the signature of Tc and has a significantly weaker temperature dependence in the superconducting state than would be predicted by the Mattis–Bardeen theory. At higher frequencies, the slope tends to change by a smaller amount. No indication of collective modes at any of the frequencies was observed down to the lowest temperatures measured (∼0.1 K). 相似文献
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Lei Chen Jing Zuo Yanyan Lu Hai Huang 《Physica C: Superconductivity and its Applications》2011,471(23-24):1591-1594
Based on two-band Ginzburg–Landau theory, we study the temperature dependence of upper critical field for superconducting crystal NbSe2. The results reproduce the experimental data in a broad temperature range, especially the upward curvature near the transition temperature. Our calculations also indicate that in NbSe2 the band with the smaller gap is almost isotropic, and most probably located on the bonding Nb Fermi sheets. 相似文献
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We report ac susceptibility measurements of polycrystalline CePt(3)Si down to 60 mK and in applied fields up to 9 T. In a zero applied field, a full Meissner state emerges at temperatures T/T(c) < 0.3, where T(c) = 0.65 K is the onset transition temperature. Though transport measurements show a relatively high upper critical field B(c2) approximately 4-5 T, the low-temperature susceptibility chi(') is quite fragile to the applied field, with chi(') diminishing rapidly in fields of a few kG. Interestingly, the field dependence of chi(') is well described by the power law 4pichi(') + 1 = (B/B(c))(1/2), where B(c) is the field at which the onset of resistance is observed in transport measurements. 相似文献
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B. Wolf R. Blick G. Bruls B. Lüthi Z. Fisk J. L. Smith H. R. Ott 《Zeitschrift für Physik B Condensed Matter》1991,85(2):159-160
In UBe13 magnetoacoustic quantum oscillations (MAQO) are observed for the attenuation- and the sound velocity-changes in the superconducting and normal state. The observed extremal areas and the effective masses are small. 相似文献
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Detlef Lehmann 《Communications in Mathematical Physics》1995,173(1):155-174
The propagator for a noninteracting many electron system in a constant magnetic field in three space time dimensions is computed. This formula and the results of [FT1,2] are used to give a microscopic derivation of a BCS-equation with magnetic field. It is shown that this equation has no solution if the magnetic field is sufficiently large. Perturbation theory in the interaction around the magnetic field propagator is discussed. 相似文献