Influence of the deGennes extrapolation parameter on the resistive state of a superconducting strip

Abstract

We studied the resistive state of a mesoscopic superconducting strip (bridge) at zero external applied magnetic field under a transport electric current, J a , subjected to different types of boundary conditions. The current is applied through a metallic contact (electrode) and the boundary conditions are simulated via the deGennes extrapolation length b. It will be shown that the characteristic current-voltage curve follows a scaling law for different values of b. We also show that the value of J a at which the first vortexantivortex (V-Av) pair penetrates the sample, as well as their average velocities and dynamics, strongly depend on the b values. Our investigation was carried out by solving the two-dimensional generalized time dependent Ginzburg-Landau (GTDGL) equation.

Resistive state of a thin superconducting strip with an engineered central defect

“…At a certain value of J a , there is an inversion where the kinematic vortices nucleate; they are formed at the edges and then are annihilated at the center phase R-II. The two resistive phases are delimited by the local maximum of the I-R curve, as we stated previously [4,5].…”

“…This was first proposed by Andronov et al and later observed experimentally by Sivakov et al [1,2]. They consist of V-Av pairs that move at a much larger velocity than a normal Abrikosov vortex [1][2][3][4][5][6][7][8][9]. Several theoretical and experimental investigations have been performed on superconductors with defects in the presence of external applied transport currents.…”

“…This last point will be discussed in more detail in the next subsection. In the interval J c2 ≤ J a ≤ J c3 , the system is in a partially normal state, where the superconductivity is nearly destroyed in the whole bridge, except at the corners [4,5]. Above J c3 , the normal state sets in.…”

“…A superconducting strip under an external applied dc current density through two metallic contacts is simply abbreviated by the expression superconducting bridge (see Ref [4]…”

Simple theoretical proposal of the dependence of the deGennes extrapolation parameter with the surface temperature of a superconducting sample

“…[7]. Fink et al studied the effect of the presence of another material in contact with the superconducting sample (simulated by ) [3,5] on for various geometries. They found that the deGennes parameter is useful to analyze the variation of T c in mesoscopic superconductors [8].…”