Superconductivity critical transition temperature

Superconductivity is the sudden and complete disappearance of electrical resistance in a substance when it is cooled below a certain temperature, called the critical transition temperature, Tc. 

Superconductivity is a phenomenon characterized by sudden and complete disappearance of electrical resistance in a substance when it is cooled below a certain tempeSrature, called the critical transition temperature, T. Superconductivity was discovered in 1911 by measuring the resistance of solid mercury (Hg) on cooling with a sharp discontinuity in resistance at about 4.2 K (see Fig. 1). In addition to the total loss... 

X-ray and electron diffraction methods are applied in order to measure atomic distances in the crystal lattice and their changes. Hence, the diffraction methods are also basically suitable for measuring the strain/stress behaviour in thin films. However, since the film thickness and the crystallite size in thin films are small, some line broadening already arises from this. In order to determine what contribution the mechanical stresses have on the diffuse lines, careful analysis of the line profiles must be undertaken [148, 151]. This method is less suitable for routine determination of stresses in thin films. In some cases, it is possible though rarely applied to determine the stresses in the films through their influence on other, known film properties, at least approximately. Such properties are, for example, the position of an absorption edge [152], the Hall effect [153], electron spin resonance spectra [155] and in the case of superconducting films, variations in the critical transition temperature [156]. However, these effects can, unfortunately, also arise for other reasons, and thus these techniques can usually only be used as supplemental experiments. 

Iridium becomes superconducting below 0.11 K. Some ternary alloys show critical transition temperatures between 3 K and above 8 K (Table 3.1-256) [1.218... 

Ruthenium shows superconductivity below 0.47 K [1.218]. Ternary alloys have critical transition temperatures up to 12.7 K (Table 3.1-264). 

Table3.1-264 Critical transition temperature of superconducting Ru alloys [1.218, p. 636] ...

Table 4.2-24 Superconducting properties (transition temperature Tc, coherence length, penetration depth k, GL coefficient tc, lower critical field Hd, upper critical field Hc2) for YBCO [2.54]...

The inset of Fig. 2 shows that the generalization of the BCS relation Tc 0.57 A(T = 0. fiq) g(pq), between the critical temperature Tc of the superconducting phase transition and the pairing gap A at T = 0 is satisfactorily fulfilled in the domain of the phase diagram relevant for compact stars. 

Figure 3. Phase diagrams for different form-factor models Gaussian (solid lines), Lorentzian a = 2 (dashed lines) and NJL (dash-dotted). In /3-equilibrium, the colorsuperconducting phase does not exist for Co Gi. In the inset we show for the Gaussian model the comparison of the numerical result with the modified BCS formula Tf = 0.57 A(T = 0, fiq) g(Hq) for the critical temperature of the superconducting phase transition.

We have investigated the influence of diquark condensation on the thermodynamics of quark matter under the conditions of /5-equilibrium and charge neutrality relevant for the discussion of compact stars. The EoS has been derived for a nonlocal chiral quark model in the mean field approximation, and the influence of different form-factors of the nonlocal, separable interaction (Gaussian, Lorentzian, NJL) has been studied. The model parameters are chosen such that the same set of hadronic vacuum observable is described. We have shown that the critical temperatures and chemical potentials for the onset of the chiral and the superconducting phase transition are the lower the smoother the momentum dependence of the interaction form-factor is. 

Fig. 5.10 The mass dependence of the critical temperature of the superconducting/resistive transition in isotopically enriched samples of mercury (Triangles Reynolds, C. A., et al. Phys. Rev. 78, 487 (1950). Circles Maxwell, E., Phys. Rev. 78, 477 (1950))...

The amount and positions (atomic locations) of oxygen atoms in the superconductors are highly critical and determine the properties of the superconductor. The oxygen vacancies (or deficiency) can be ordered in these materials. Neutron-diffraction experiments were required to determine the population parameters and the atomic positions of oxygen in these structures. The superconducting transition temperature in these "ceramic" oxides is a critical balance between the oxygen content and a proper mix of Cu2+ and Cus+ ions generated in the anneal or post-heat treatment. 

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