Three-dimensional superconductivity in the infinite-layer compound Sr0.9La0.1CuO2 in entire region below Tc

Abstract

The infinite-layer compound ACuO2 (A = alkaline-earth ions) is regarded as the most suitable material for exploring the fundamental nature of the CuO2 plane because it does not contain a charge-reservoir block, such as a rock-salt or a fluorite like block. We report that superconductivity in the infinite-layer compound Sr0.9La0.1CuO2 is of a three-dimensional nature, in contrast to the quasi two-dimensional superconducting behavior of all other cuprates. The key observation is that the c-axis coherence length is longer than the c-axis lattice constant even at zero temperature. This means that the superconducting order parameter of one CuO2 plane overlaps with those of neighboring CuO2 planes all the temperatures below the Tc. Among all cuprates, only the infinitelayer superconductor shows such a feature.

Anisotropy and reversible magnetization of the infinite-layer superconductorSr0.9La0.1CuOKim1, Lemberger2, Jung3 et al. 2002Phys. Rev. BSelf Cite29391View full textAdd to dashboardCite

“…More concrete evidence for this can be found from a scaling analysis of the fluctuation-induced magnetization for the high-field region. 20,21 In our previous report, 22 we showed that the high-field magnetization scales excellently with the scaling parameter ͓TϪT c (H)͔/ (TH) 2/3 , implying weak fluctuation effects. perature T irr (H) is defined as the temperature at which the simple criterion M FC /M ZFC ϭ0.98 holds.…”

Bulk evidence for s -wave pairing symmetry in electron-doped infinite-layer cuprate Sr 0.9 La 0.1 CuO 2

“…It is known that the Simon-Lee scaling law is applicable with T T c and H H c2 (0). Taking T c = 43 K and H c2 (0) = 14 T [29], one may argue that the inapplicability of Simon-Lee scaling law here is due to the relatively high field used. From fig.…”

“…However, this cannot be the case since the main contribution from the Doppler shift effect is induced by the field component parallel to the c-axis, provided the sample is anisotropic (the anisotropy is about 9, as shown in ref. [29]). Therefore, the d-wave scaling law should be roughly valid for granular samples if it had a d-wave symmetry.…”

Dimensionality of superconductivity and vortex dynamics in the infinite-layer cuprateSr0.9M0.1CuO2Zapf1, Yeh2, Beyer3 et al. 2005Phys. Rev. B171120View full textAdd to dashboardCite

“…On the other hand, they also find significant anisotropy be-tween magnetic fields H ≤ 5 T oriented parallel and perpendicular to the CuO 2 planes, with an anisotropy ratio γ = ξ c /ξ ab = H ab c2 /H c c2 = 9.3, which is larger than γ = 5 observed in YBa 2 Cu 3 O 7−δ although much smaller than γ = 55 observed in optimally doped Bi 2 Sr 2 CaCu 2 O 8−δ . [5,11,12,13] It is interesting to note that the only major crystallographic difference between the a-b and the c directions in Sr 0.9 La 0.1 CuO 2 is the presence of oxygen in the a-b plane, which allows coupling of adjacent Cu spins and has been implicated as the cause of antiferromagntic ordering or spin fluctuations in other members of the high-T c cuprate family, as well as a possible mechanism for superconducting pairing. The importance of the CuO 2 planes to the SC in Sr 0.9 M 0.1 CuO 2 is further supported by the fact that Ni substitution on the Cu site rapidly suppresses T c whereas out-of-plane Gd substitution on the Sr site leaves T c unchanged.…”