Magnetic excitation superconduction transition

At this point we want to stress that the heavy fermion systems (22) are related to a very large spin enhanced susceptibility or localized magnetic moments, very narrow bands of elementary excitations at the Fermi level, and a new type of pairing, in the case where they become superconducting, at low temperatures even if they were spin fluctuators above the critical superconducting transition temperature Tg. 

GPa with magnetic fields up to 0.7 T, parallel to the excitation current direction. The resistivity drop is suppressed by magnetic field and disappears above 0.7 T. This is a further direct evidence of the superconducting transition in CePtSi2. Field dependence of Tc is displayed in the inset (A) of Figure 116. The upper critical field Hcz is foimd to be 0.7 T at... 

The Meissner effect is a very important characteristic of superconductors. Among the consequences of its linkage to the free energy are the following (a) The superconducting state is more ordered than the normal state (b) only a small fraction of the electrons in a solid need participate in superconductivity (c) the phase transition must be of second order that is, there is no latent heat of transition in the absence of any applied magnetic field and (d) superconductivity involves excitations across an energy gap. 

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