Specific heat of MgB2 after irradiation

  title={Specific heat of MgB2 after irradiation},
  author={Yuxing Wang and Fr{\'e}d{\'e}ric Bouquet and I. Sheikin and Pierre Toulemonde and Bernard Revaz and Michael Eisterer and Harald W. Weber and Joerg Hinderer and Alain F. Junod},
  journal={Journal of Physics: Condensed Matter},
We studied the effect of disorder on the superconducting properties of polycrystalline MgB2 by specific-heat measurements. In the pristine state, these measurements give a bulk confirmation of the presence of two superconducting gaps with 2Δ0/kBTc = 1.3 and 3.9 with nearly equal weights. The scattering introduced by irradiation suppresses Tc and tends to average the two gaps although less than predicted by theory. We also found that by a suitable irradiation process by fast neutrons, a… Expand
36 Citations

Tables from this paper

Using specific heat to scan gaps and anisotropy of MgB2
Abstract We performed specific heat measurements to study the superconducting properties of the ∼40 K superconductor MgB 2 , up to 16 T, using polycrystal and single crystal samples. Our resultsExpand
Evolution of the structure and properties of the MgB2 superconductor under isothermal annealing
The effect of comparatively weak actions on the structure of the two-gap BCS superconductor MgB2 was studied. The MgB2 samples studied differed in terms of the annealing time at 900°C. It was foundExpand
Effects of neutron irradiation on carbon doped MgB2 wire segments
We have studied the evolution of superconducting and normal state properties of neutron irradiated Mg(B0.962C0.038)2 wire segments as a function of post-exposure annealing time and temperature. TheExpand
Radiation damaged MgB2: a comparison with A15 superconductors
In the present paper we discuss in detail experiments of radiation damage and their effects on MgB2 properties (Tc, resistivity, critical field, gap), making constant reference to similar experimentsExpand
Superconducting properties of nanocrystalline MgB2
Nanocrystalline MgB2 produced by mechanical alloying has been shown to exhibit enhanced superconducting properties such as increased pinning and higher critical currents. However, the effects of theExpand
Magnetic properties and critical currents of MgB2
This review focuses on the superconducting properties of MgB2 that are relevant for power applications. The reversible mixed state parameters are the most important, since they define the limitingExpand
Observation of the gap merging in neutron irradiated MgB2
Abstract We measure specific heat on neutron-irradiated MgB 2 samples, whose critical temperature is reduced down to 8.7 K keeping the superconducting transition extremely sharp. The results clearlyExpand
Effect of electron irradiation on the structure and properties of the MgB2 superconductor
This paper reports on the results of an investigation into the effect of irradiation of the Bardeen-Cooper-Schriefer superconductor MgB2 by electrons with a mean energy Ē ∼ 10 MeV at low doses (0 ≤Expand
Limits of the upper critical field in dirty two-gap superconductors
Abstract An overview of the theory of the upper critical field in dirty two-gap superconductors, with a particular emphasis on MgB2 is given. We focus here on the maximum Hc2 which may be achieved byExpand
Nonmagnetic Impurity Effects in MgB2
We study nonmagnetic impurity effects in MgB 2 using the quasiclassical equations of superconductivity for a weak-coupling two-band model. Parameters in the model are fixed so as to reproduceExpand


Evidence for two superconducting energy gaps in MgB(2) by point-contact spectroscopy.
Evidence is obtained for two distinct superconducting energy gaps in the multiband model of the superconductivity in the recently discovered system MgB(2) with the transition temperature T(c) = 39 K by means of Andreev reflection. Expand
Specific heat of single crystal MgB2: a two-band superconductor with two different anisotropies.
Heat-capacity measurements of a 39 microg MgB2 single crystal in fields up to 14 T and below 3 K allow the determination of the low-temperature linear term of the specific heat, its field dependence,Expand
Phenomenological two-gap model for the specific heat of MgB2
The authors show that the specific heat of the superconductor MgB{sub 2} in zero field, for which significant non-BCS features have been reported, can be fitted, essentially within experimentalExpand
Field Dependence of Electronic Specific Heat in Two-Band Superconductors
The vortex structure is studied in light of MgB 2 theoretically based on a two-band superconducting model by means of Bogoliubov-de Gennes framework. The field dependence of the electronic specificExpand
Temperature and field dependence of the anisotropy of MgB2.
The anisotropy gamma of the superconducting state of high quality single crystals of MgB2 was determined, using torque magnetometry with two different methods, finding the unusual temperature dependence and can be explained by nonlocal effects of anisotropic pairing and/or the k--> dependence of the effective mass tensor. Expand
Enhancement of the high-magnetic-field critical current density of superconducting MgB2 by proton irradiation
It is shown that modest levels of atomic disorder induced by proton irradiation enhance the pinning of vortices, thereby significantly increasing Jc at high field strengths, and it is anticipated that either chemical doping or mechanical processing should generate similar levels of disorder, and so achieve performance that is technologically attractive in an economically viable way. Expand
Boron isotope effect in superconducting MgB2.
The preparation method of and boron isotope effect for MgB2, a new binary intermetallic superconductor with a remarkably high superconducting transition temperature T(c)(10B) = 40.2 K, is reported, consistent with the material being a phonon-mediated BCSsuperconductor. Expand
Specific heat of MgB2 in a one- and a two-band model from first-principles calculations
The heat capacity anomaly at the transition to superconductivity of the layered superconductor MgB2 is compared to first-principles calculations with the Coulomb repulsion, µ*, as the only parameterExpand
Exponential temperature dependence of the penetration depth in single crystal MgB2.
The temperature dependence of the London penetration depth, lambda(T), was measured in both single crystal and polycrystalline MgB2 samples by a high-resolution, radio frequency technique and it is found that the data are best described by a two-gap model. Expand
First-Principles Calculation of the Superconducting Transition in MgB2 within the Anisotropic Eliashberg Formalism
We present a study of the superconducting transition in MgB2 using the ab initio pseudopotential density-functional method, a fully anisotropic Eliashberg equation, and a conventional estimate forExpand