排序方式: 共有34条查询结果,搜索用时 31 毫秒
1.
Urbano RR Pagliuso PG Rettori C Kopelevich Y Moreno NO Sarrao JL 《Physical review letters》2002,89(8):087602
We report the first observation of the field distribution and flux-line lattice (FLL) depinning in the vortex-state (VS) of a type-II superconductor probed by conduction electron spin resonance (CESR). CESR was performed in MgB (2) (T(c) approximately 39 K) at 4.1 GHz (1455 Oe) and 9.5 GHz (3390 Oe). The field distribution, n(H), and a standard deviation of sigma approximately 14 Oe (at 28 K/4.1 GHz and at 7 K/9.5 GHz) were inferred, respectively, from the distortion and broadening of the CESR in the VS. For both frequencies, the FLL depinning temperature was determined. 相似文献
2.
Cornelius AL Lawrence JM Ebihara T Riseborough PS Booth CH Hundley MF Pagliuso PG Sarrao JL Thompson JD Jung MH Lacerda AH Kwei GH 《Physical review letters》2002,88(11):117201
Experimental results for the susceptibility, magnetization, specific heat, 4f occupation number, Hall effect, and magnetoresistance for single crystals of the intermediate valence (IV) compound YbAl3 show that, in addition to the Kondo temperature scale T(K) approximately 670 K, there is a low temperature scale T(coh) approximately 30-40 K for the onset of Fermi liquid coherence. Furthermore, the crossover from the low temperature Fermi liquid regime to the high temperature local moment regime is slower than predicted by the Anderson impurity model. We suggest that these effects are generic for IV compounds and we discuss them in terms of the theory of the Anderson lattice. 相似文献
3.
Llobet A Christianson AD Bao W Gardner JS Swainson IP Lynn JW Mignot JM Prokes K Pagliuso PG Moreno NO Sarrao JL Thompson JD Lacerda AH 《Physical review letters》2005,95(21):217002
The heavy fermion system exhibits properties that range from an incommensurate antiferromagnet for small to an exotic superconductor on the Ir-rich end of the phase diagram. At intermediate where antiferromagnetism coexists with superconductivity, two types of magnetic order are observed: the incommensurate one of and a new, commensurate antiferromagnetism that orders separately. The coexistence of -electron superconductivity with two distinct -electron magnetic orders is unique among unconventional superconductors, adding a new variety to the usual coexistence found in magnetic superconductors. 相似文献
4.
Among heavy-fermion (HF) superconductors, CeCoIn 5 exhibits a record high value of T c =2.3 K at ambient pressure [1]. CeCoIn 5 belongs to a new class of HF-superconductors that crystallize in the tetragonal HoCoGa 5 -structure. This structure can be regarded as alternating layers of CeIn 3 and CoIn 2 . Bulk CeIn 3 undergoes a transition from an antiferromagnetic (AFM) state at ambient pressure ( T N =10.2 K) to a superconducting state with very low T C =0.15 K at a critical pressure p c =2.8 GPa [2] at which long range magnetic order vanishes. It is, therefore, regarded as a possible candidate for magnetically mediated superconductivity (SC). We report on measurements of the heat capacity of CeCoIn 5 at hydrostatic pressures p h 1.5 GPa. While T c increases with increasing pressure, the effective mass of the quasi-particles m eff decreases, as indicated by the ratio C / T | T c . As a working hypothesis based on theories of a nearly antiferromagnetic Fermi-liquid (NAFFL), this may be interpreted as the stabilization of the superconducting state by an increase of the characteristic spin fluctuation temperature T_{SF} (T_{SF}\propto k_F^2/m_{\rm eff}). 相似文献
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6.
Daniel M Bauer ED Han SW Booth CH Cornelius AL Pagliuso PG Sarrao JL 《Physical review letters》2005,95(1):016406
In contrast to substitution on the Co or Ce site, Sn substitution has a remarkably strong effect on superconductivity in CeCoIn5-xSnx, with Tc-->0 beyond only 3.6% Sn. Instead of being randomly distributed on in-plane and out-of-plane In sites, extended x-ray absorption fine structure measurements show the Sn atoms preferentially substitute within the Ce-In plane. This result highlights the importance of the In1 site to impurity scattering and clearly demonstrates the two-dimensional nature of superconductivity in CeCoIn5. 相似文献
7.
Bittar EM Adriano C Garitezi TM Rosa PF Mendonça-Ferreira L Garcia F Azevedo Gde M Pagliuso PG Granado E 《Physical review letters》2011,107(26):267402
The Fe K x-ray absorption near edge structure of BaFe(2-x)Co(x)As(2) superconductors was investigated. No appreciable alteration in shape or energy position of this edge was observed with Co substitution. This result provides experimental support to previous ab initio calculations in which the extra Co electron is concentrated at the substitute site and do not change the electronic occupation of the Fe ions. Superconductivity may emerge due to bonding modifications induced by the substitute atom that weakens the spin-density-wave ground state by reducing the Fe local moments and/or increasing the elastic energy penalty of the accompanying orthorhombic distortion. 相似文献
8.
The LaIn(3-x)Sn(x) alloy system is composed of superconducting Pauli paramagnets. For LaIn3 the superconducting critical temperature T(c) is approximately 0.7 K and it shows an oscillatory dependence as a function of Sn substitution, presenting its highest value T(c) ≈ 6.4 K for the LaSn3 end member. The superconducting state of these materials was characterized as being of the conventional type. We report our results for Gd3+ electron spin resonance measurements in the LaIn(3-x)Sn(x) compounds as a function of x. We show that the effective exchange interaction parameter J(fs) between the Gd3+ 4f local moment and the s-like conduction electrons is almost unchanged by Sn substitution and observe microscopically that LaSn3 is a conventional superconductor. 相似文献
9.
Mendonça Ferreira L Park T Sidorov V Nicklas M Bittar EM Lora-Serrano R Hering EN Ramos SM Fontes MB Baggio-Saitovich E Lee H Sarrao JL Thompson JD Pagliuso PG 《Physical review letters》2008,101(1):017005
Pressure- and temperature-dependent heat capacity and electrical resistivity experiments on Sn- and La-doped CeRhIn5 are reported for two samples with specific concentrations, Ce(0.90)La(0.10)RhIn5 and CeRhIn(4.84)Sn(0.16), which present the same TN=2.8 K. The obtained P-T phase diagrams for doped CeRhIn5 compared to that for the pure compound show that Sn doping shifts the diagram to lower pressures while La doping does exactly the opposite, indicating that the important energy scale to define the pressure range for superconductivity in CeRhIn5 is the strength of the on-site Kondo coupling. 相似文献
10.
T. M. Garitezi C. Adriano P. F. S. Rosa E. M. Bittar L. Bufaiçal R. L. de Almeida E. Granado T. Grant Z. Fisk M. A. Avila R. A. Ribeiro P. L. Kuhns A. P. Reyes R. R. Urbano P. G. Pagliuso 《Brazilian Journal of Physics》2013,43(4):223-229
We report a detailed characterization of BaFe2As2 single crystals grown by a metallic In-flux technique, an alternative to well-established growth routes using FeAs self- or Sn-flux. Electrical resistivity, magnetic susceptibility, nuclear magnetic resonance, and energy dispersive spectroscopy measurements showed no evidence of flux incorporation. More importantly, our results demonstrate that BaFe2As2 single crystals grown by In-flux have extremely high quality. To explore the efficiency of the In-flux growth method, we have also prepared nearly optimally doped superconducting samples of Ba(Fe1 ?x M x )2As2 (M = Co, Cu, Ni, and Ru). Among other interesting features, this alternative chemical substitution method has led to enhancement of the maximum T c for most dopings. 相似文献