Landau parameters

Eqs. (9),(11) the condition eq. (12) in the random phase approximation (RPA) formalism leads to a self-consistency relation between the symmetry potential and the Landau parameter F [26] ... 

Table 2 Coherence length f, penetration depth X, and Ginzburg-Landau parameter k =Xj for various superconductors...

These values allow one to evaluate the penetration depth X = 2400 A and the coherence length I s 26 A, and hence a Ginz-buig-Landau parameter k X/ around 100, an extremely high value approaching that of the high-Tc copper oxides. 

TiBe2 has the C15 cubic Laves phase structure and is an itinerant antiferromagnet with a Neel temperature near 10 K and a magnetic moment of 1.64jub. The Laves phase can be maintained when Cu is substituted for Be over the range 0 < x < 0.5 and a transition to ferromagnetism is observed at xcrit 0.115 (Acker et al. 1981) near which the SEW behaviour, i.e. the Landau parameter in the magnetic equation of state... 

Properties and microscopic parameters characterizing the normal and superconducting states of polycrystalline heavy-fermion superconductors T, from speciflc-heat measurements B and, slopes of upper and lower critical-field curves at T p , normal-state (T — 0) resistivity 1, total mean free path I, Ginzburg-Landau coherence length A, London penetration depth k, Ginzburg-Landau parameter 0) B, , B j(T—>0). The other... 

E-representations through the last term in eq. (69). Whereas at low temperature the stable state is determined by the fourth order terms, close to Td the second order terms yo > 0 dominate and favor a single component state, only below Tc2 will the second component be nonzero. One has two phases (A) rj = r](l, 0) below Td and (B) rj = r](l,ai) below Tc2- The Tc 1,2-splitting and the difference in amplitudes (a < 1) in the 5-phase are determined by the Landau parameters according to... 

Earlier [14] a ratio connecting the Ginsburg-Landau parameter % of niobium with the value of specific electroresistivity p was obtained ... 

As described above, there is some correspondence between the bilinear/ biquadratic P-9 couplings of the phenomenological Landau model and the polar/quadrupolar rotational potentials of the microscopic model. Indeed, the most pronounced deviation from a proportionality between P and 9, the sign inversion of Pg, can be obtained in both models, either by assuming certain values of the Landau parameters [41] or, in the molecular rotation description, by a slight modification of the rotational potential (8.2) [42]. 

The number of Landau parameters in Eq. (64) can be reduced by an apropriate straightforward rescaling of variables ... 

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