Superconducting phase transition

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. 

Salje EKH, Wruck B (1983) Specific-heat measurements and critical exponents of the ferroelastic phase transitioninPb3(P04)2andPb3(Pi xAsx04)2. PhysRevB 28 6510-6518 Salje EKH, Yagil Y (1996) Hard mode spectroscopy for the investigation of structural and superconducting phase transitions. J Phys Chem Solids 57 1413-1424... 

Fig. 10. Crystal-field splitting of the Gd-resonance line in LaOsj at various temperatures below the superconducting phase transition. The experimental values (b) are compared with simulated spectra using different values of (a and c). From Luft and Baberschke (1981).

Fig. 5. Temperature dependence (a) of the intensity of the absorption line, (b) of the g-factors, gj and gj, and (c) of the linewidth in YBa2Cu306g. Due to a strong increase of the linewidth the EPR signals are lost well above the superconducting phase transition temperature.

The second important piece of information from EPR experiments was collected about the slowing down of the spin fluctuations. Most of the EPR experiments, at least in slightly underdoped materials, show a strong increase of the linewidth towards low temperatures. This behavior seems to be compatible with the slowing down of the characteristic frequencies of the spin fluctuations. These EPR results have to be compared with NMR results which can be interpreted by the opening of a spin-gap well above the superconducting phase-transition temperature in the underdoped samples. In this... 

Temperature sensor using a superconducting phase transition edge (H h sensitivity, low noise)... 

A dual-shell model describes the Tq for ferromagnetic, ferroelectric, and superconductive phase transitions because of the involvement of both the long-and the short-range interactions. 

Critical temperatures (Tc) that are related to atomic cohesive energy represent the thermal stability of a specimen such as solid-liquid, liquid-vapor, or ferromagnetic, ferroelectric, and superconductive phase transitions, or glass transition in amorphous states. 

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