Explanation of the resistance-peak anomaly in nonhomogeneous superconductors

The role of density of states fluctuations in the normal state properties of highTcsuperconductors

“…An early review of thē uctuation e ects on the electrical transport properties was given in [129]. As pointed out in [130,131] earlier measurements, especially when carried out on bulk single crystals, were sometimes a ected by Tc (oxygen content) inhomogeneities. Such di culties were surmounted mostly by using monocrystalline ® lms with well de® ned geometries.…”

Transverse voltage and chiral glass transition inYBa2Cu3O6+dSobociński1, Grande2, Pureur3 2014Physica C: Superconductivity and its Applications3050View full textAdd to dashboardCite

“…3 and 4 for samples Y2 and Y3, respectively, have been reported in HTSC and other superconductors [8][9][10]16,[12][13][14]. A quite well accepted interpretation for this behavior in V t invokes the occurrence of nonuniform current due to inhomogeneity along the transverse orientation of the film [10,12,14]. In order to check for this possibility for describing our results, we estimate the excess transverse voltage by subtracting the scaled longitudinal voltage from the V t data, that is…”

“…This extrinsic effect also occurs in the presence of an applied field, but unlike the Hall effect, dV xy is even in field. The excess transverse voltage was first reported to occur in YBa 2 Cu 3 O 6þd thin films [7,9], but similar observations were made in thin films of conventional metallic superconductors [9][10][11]. The excess transverse voltage takes place in a short temperature interval in the close vicinity of the superconducting transition temperature T c .…”

“…Thus, it has been proposed that effects from a nonuniform electrical current lead to a plausible explanation for the transverse voltage anomaly near T c in inhomogeneous superconducting samples [10,12,14,19]. Indeed, due to the sharp resistivity variation at T c , even minor deviations of the strict homogeneity in the orientation perpendicular to the current may produce sizeable dV xy [14].…”

At the interface between electron and hole-doped cuprates

“…Here, an upturn in the resistance is observed above T c , indicating a shift to lower doping by oxygen inclusion [45], increased impurity scattering and carrier localization [44,105]. These samples show a broad superconducting transition with a small upturn at T c , characteristic of sheet measurements on inhomogeneous superconductors with an out-of-line contact arrangement [107], see figure 2.4(b). We find the highest T c for films annealed for 45 min in vacuum.…”