Superconducting diamagnetic fluctuations for H ∥ ab planes in YBa2Cu3O7−δ for fields up to 5 T

Experimental observation of high-field diamagnetic fluctuations in niobium

“…5,6,8 -13 An important check of the scaling is that it should provide reasonable values of T c (H). 6,8 For lower-dimensional or layered materials, the LLL analysis also helps to explain the crossing points observed in M (T) curves. [9][10][11]13,14 Despite the relevance of LLL fluctuations for HTSC's there are few comparable studies in conventional superconductors.…”

Superconducting fluctuations for three-dimensional anisotropic superconductors in the presence of a magnetic field with arbitrary direction

“…Recently measurements have been reported for the magnetization in YBa 2 Cu 3 O 7Ϫ␦ single crystals for applied magnetic fields parallel to the ab planes ͑perpendicular to the c axis͒. 5,6 These experimental results are the motivation to generalize Tesanovic's results in the limit of the anisotropic 3D superconductor for the case of an arbitrary direction of the applied magnetic field.…”

“…In the last years interest has grown in the study of properties of strongly type-II superconductors such as hightemperature superconductors ͑HTSC's͒, fullerene superconductors, superconducting superlattices, etc. The behavior in the vicinity of H c2 (T) is strongly influenced by the thermodynamic fluctuations and many experimental [1][2][3][4][5][6] as well as theoretical [7][8][9][10][11][12][13][14] results have been reported in relation to the critical behavior arising as a consequence of the thermal fluctuations in these systems. For ordinary superconductors, the superconducting transition is very well described by the Ginzburg-Landau theory ͑GL͒, which was shown by Gorkov to be equivalent to the BCS theory in the limit T→T c .…”

Thermodynamic Scaling Functions of Three-Dimensional Anisotropic Superconductors in the Presence of a Magnetic Field with Arbitrary Direction

“…The behavior of high-temperature superconductors (HTSCs) in the vicinity of the upper critical magnetic field H c2 T is strongly influenced by the thermodynamic fluctuations. Measurements of magnetization [1,2] and specific heat [3] have shown a typical three-dimensional (3D) behavior of YBa 2 Cu 3 O 7Àd in the region of transition. Tesanovic and co-workers [4,5] have developed a nonperturbative theory of critical behavior for anisotropic superconductors for both 2D and 3D systems in the presence of strong magnetic fields applied in the direction parallel to the c-axis, describing the critical behavior by means of an interacting particle system with long-ranged multiple-body forces (dense vortex plasma).…”

“…2 the calculated scaling functions for magnetization are compared with experimental data of Refs. [1,2], for magnetic fields parallel ( Fig. 2a) and perpendicular (Fig.…”