Resistivity anomalies above the superconducting transition in Y1Ba2Cu3O7−δ crystals and non-uniformly distributed critical-temperature inhomogeneities

Giant Resistive Peak Close to The Superconducting Transition in Bi2Sr2CaCu2O8 Single Crystals

“…This is similar to what is observed in other HTS single crystals [2][3]. The ab-plane resistivity in the normal state can be fitted as PN(T) = AT+B (see the dashed lines in Fig.2 Fig.…”

“…The powders of Bi 2 03r srcolt caco 3 and cuo (99.99%) in their metal ratios were mixed and ground in agate mortar, then place in an Al 2 0 3 crucible and calcined first for 48 hrs at 810 °C. The calcined powders were then reground and calcined for 72 hrs at 840 °C for feed rods, and 820 oc for solvent materials.…”

“…In the case of high-temperature superconductors (HTS) the granularity behaviour has been strongly enhanced, mainly due to a very short superconducting coherence-length which is of the order of the interatomic distances. Granularity has been observed in the single crystals of HTS systems, such as ~_,ce,cuo 4 _Y ( L=Pr, Nd, Sm) [ 2] , YBa 2 Cu307_Y ( YBCO) [3) , etc. and i t has been argued that intrinsic granularity can be at the origin of the controversy between Lorentz-force versus non-Lorentz-force-based dissipation mechanism in some HTS (4).…”

Hole-Filling above Tc, at the Origin of the In-Plane Resistivity Anomaly in Bi-2212 Crystals

“…In the work of Han et al the relative intensity of the anomaly is 180%, T A 94 K, DT A 2 K and T c0 93 K. These results are analogous to ours, and we think that both cases share a common origin. The explanation given by Han et al is identical to the one previously suggested by [1,2] for YBCO: an extension to single crystals (expected to be inhomogeneous) of the doublepeak superconducting transition occurring in granular superconductors. This quasi-reentrant behaviour is generally very smooth even in the case of a granular superconductor and, consequently, cannot be relevant in the case of the sharp anomaly of our slightly inhomogeneous single crystal.…”

“…An anomaly, about 20% in intensity, had first been observed in the in-plane resistivity versus temperature curves, r ab T, in the case of underdoped YBa 2 Cu 3 O 7Àx (YBCO) crystals [1,2]. Because of its smooth character, rather similar to the characteristic double-peak superconducting transition of granular superconductors (as described by Gerber et al [3]), it was expected to be the consequence of some crystal inhomogeneities.…”