Specific-heat studies of neutron-irradiatedA15Nb3Al

Abstract

The specific heat of neutron-irradiated Nb3A1 has been measured in the temperature range 1.3 -25 K for fluences of 1.3 X10 and 1.3 X10 nlcm (E & 1 MeV). A reduction in the superconducting transition temperature is accompanied by an increase in transition width with increasing fluence. The Debye temperature increases 20'/0, and the electronic density of states shows a slight decrease that is within error limits, relative to the unirradiated material.

Structural Tuning of Unconventional Superconductivity inPuMGa5(M=Bauer1, Thompson2, Sarrao3 et al. 2004Phys. Rev. Lett.Self Cite

“…This power law behavior of CeCoIn 5 is in agreement with the fourfold modulation of angular dependent thermal conductivity measurements in magnetic fields below H c2 , indicative of an unconventional d x 2 ÿy 2 superconducting order parameter symmetry [19]. The normalized electronic specific heat C el =T c vs T=T c ( is the value of the electronic specific heat at T c ) of CeCoIn 5 , PuCoGa 5 , and the A-15 compound Nb 3 Al [20] is shown in Fig. 1(b).…”

“…Inset: C el T=T of CeCoIn 5 (left axis), PuCoGa 5 , and Nb 3 Al (right axis). (Data from Refs [17,20]…”

The effect of critical coupling constants on superconductivity enhancement

“…2a. Specifically, when the Ge component rises from x = 0 to x = 0.29, the electrons per atom ratio (e/a) rises from 4.50 to 4.57 and T c increases from 18 to 21 K. The coupling constant of Nb 3 Al 1 is > 1.8 41 www.nature.com/scientificreports/ is consistent with the positive carrier effect. Moreover, when the Ge component rises from x = 0.29 to x = 1, the e/a ratio rises from 4.57 to 4.75 and T c decreases from 21 to 7 K. The coupling constant of Nb 3 Ge 1 is < 1 6 which is smaller than Z c and is consistent with the negative carrier effect.…”

Effect ofα-particle irradiation on a NdFeAs(O,F) thin film

“…In fact Fp,PD/Fp.S(10K) almost doubles after the final cycle with respect to the pristine sample. If L is the average distance between pinning centres, Vt can vary from (a/L) 3 in the case of rigid vortices to (a/L) in the case of perfectly flexible vortices or when L~d, with d being the vortex spacing (matching effect) [38]; Fp,PD/Fp.S assumes values between:…”

“…Irradiation of superconductors has been performed for many years to improve our fundamental knowledge of the influence of impurity scattering on the superconducting properties and to explore whether the material performance can be improved for practical applications. For instance irradiation with neutrons, α-particles or electrons of A15 phases like V 3 Si [1,2], Nb 3 Al [3], V 3 Ge [1], Nb 3 Sn and Nb 3 Ge [1,4,5] was employed to determine the effect on T c suppression, changes in the density of states (DOS) and in H c2 , variation in the gap amplitude and in the Debye temperature. More recently neutron and proton irradiation was found to favourably change the pinning landscape in order to increase both H c2 and J c in commercial Nb 3 Sn wires for accelerator magnets [6,7].…”