Phase diagram of PbBi alloys: structure-property relations and the superconducting coupling

Abstract

We report on the crystal structure transformation and superconducting phase diagrams for a PbmBi100−m (0 < m < 100 in %) alloy. The superconducting coupling strength is resolved by analyzing the dependency of TC on the applied magnetic field. The phase diagram shows evidence for strong-coupling s-wave superconductivity for all alloys of PbmBi100−m and the dependency of the superconducting parameters on the weight percent of each constituent phase is discussed in the phase diagram. Very strong coupling of 2Δo/kBTC ∼ 5.174 is observed in the present PbmBi100−m phase diagram.

Phase Diagram and Superconductivity: New Insight into the Fundamentals of InSn Bimetallic Alloys

“…According to the Eliashberg theory based on Allen and Dynes, modified from McMillan formulations, the EP coupling constant can be expressed as , where N ( E F ) gives the density of state (DOS) number at the Fermi level, ⟨ I 2 ⟩ represents Fermi surface average of the squared EP coupling interaction, M is atomic mass, and ⟨ω o 2 ⟩ is an average squared phonon frequency. From the above expression, for a known value of the DOS, high-energy phonons lead to weak EP coupling, whereas low-energy phonons lead to strong EP coupling. , Takayama et al discovered a family of ternary platinum phosphide APt 3 P (A = Sr, Ca, and La) SC with T C = 8.4, 6.6, and 1.5 K, respectively.…”

Structural and Superconducting Proximity Effect of SnPb Bimetallic Nanoalloys

“…The fitted value of p lies between 10 to 2 concerning the applied magnetic field. The obtained high value of p in a low external magnetic field is due to the flow of the shielding current around the surface of the alloy excluding the applied field detail which has been discussed in our previous work [ 20 , 21 , 22 ].…”

Niobium-titanium (Nb-Ti) superconducting joints for persistent-mode operation

“…For our superconducting joints, we selected two types of Pb-Bi alloys as solder 13 . In the first step, we checked the element composition using energy dispersive X-ray spectroscopy (EDS) because the superconductivity of Pb-Bi at 4.2 K is very sensitive to its composition and the age of the solder from the time of its manufecturing 14,15 . This is because at room temperature Bi precipitate out of superconducting phase in these Pb-Bi alloys due to solid state diffusion 15,16 .…”

“…This is because at room temperature Bi precipitate out of superconducting phase in these Pb-Bi alloys due to solid state diffusion 15,16 . In particular, a slight change in the alloy composition can result in different electrical properties 14 . Since both the solders were procured from the commercial supplier, the exact age of the solders was not known 13 .…”

“…The higher magnetic J c obtained in the Pb 44.5 Bi 55.5 can be attributed to improved flux pinning at Bi precipitates 2 . However, beyond certain Bi concentration in the Pb-Bi alloys, Bi precipitates can act as impurities, which would have eventually reduced J c of the Pb 42 Bi 58 under magnetic field compared with the Pb 44.5 Bi 55.5 14 . A comparison of the magnetic J c values reported thus far is summarized in Table S2.…”