Landau and Ott scaling for the kinetic energy density in the low-Tcconventional superconductorsLi2Pd3B

Abstract

Landau and Ott scaling for the kinetic energy density and the low T c conventional superconductors, Li 2 P d 3 B and Nb.Mauro M. Doria and S. Salem-Sugui Jr. The scaling approach recently proposed by Landau and Ott for isothermal magnetization curves is extended to the average kinetic energy density of the condensate. Two low Tc superconductors, Nb and Li2P d3B are studied and their isothermal reversible magnetization shown to display Landau and Ott scaling. Good agreement is obtained for the upper critical field Hc2(T ), determined from the Abrikosov approximation for the reversible region (standard linear extrapolation of the magnetization curve), and from the maximum of the kinetic energy curves. For the full range of data, which includes the irreversible region, the isothermal d.M.B/H 2 curves for Li2P d3B show an impressive collapse into a single curve over the entire range of field measurements. The Nb isothermal d.M.B/H 2 curves exhibit the interesting feature of a constant and temperature independent minimum value.

Discovery of Li2(Pd,Pt)3B superconductors

“…Namely, Li 2 Pd 3 B behaves as a double-gap superconductor similar to MgB 2 , while Li 2 Pt 3 B has nodes in the energy gap. The result contradicts most of the mentioned studies, refs [15,16] and penetration depth data obtained from µSR experiments [17], all of them suggesting that at least Li 2 Pd 3 B is an s-wave BCS superconductor with only one isotropic energy gap.…”

Temperature dependences of the upper critical field and the Ginzburg–Landau parameter of Li2Pd3B from magnetization measurements

“…3(a) the H c2 (T ) curve for Li 2 Pd 3 B obtained from magnetization measurements by Doria et al [10]. As may be seen, these data can also 2 In the evaluation of κ, we assume that the total volume V 0 of the sample contributes to dM/dH.…”

Superconductivity in noncentrosymmetric Ag2Pd3S

“…Recently, a number of compounds have been investigated as candidates for NCSCs [11][12][13][14][15][16][17][18][19][20][21][22][23][24], such as CePt 3 Si [4] and CeRhSi 3 [11]. These two compounds have been extensively studied by many researchers, leading to the discovery of an unusual symmetry present in the Cooper pairs.…”

“…On the other hand, Li 2 M 3 B (M = Pd,Pt) [14][15][16][17][18][19][20][21][22][23][24] are two of the appropriate compounds for forming NCSCs to investigate effects of the broken spatial inversion symmetry only. Li 2 M 3 B (M = Pd,Pt) do not contain any magnetic elements; therefore, effects of magnetic ordering can be completely ignored.…”

“…In contrast, the gap structure of Li 2 Pd 3 B has been under debate. An isotropic full gap structure is suggested by various bulk measurements such as heat capacity [16,17], whereas Yuan et al claimed by magnetic penetration depth measurements that a multigap structure consist of two gaps in which one is dominant and the other is small enough not to affect the obtained gap structure by bulk heat-capacity measurements [18]. On the other hand, Yuan et al also pointed out by precise fitting of the temperature dependence of magnetic penetration depth below T c that the gap is slightly anisotropic and there existed two gaps which had almost the same size [20].…”