Orientational pinning and transverse voltage: Simulations and experiments in square Josephson junction arrays

Article

关键词: DRIVEN VORTEX LATTICES;    PLASTIC-FLOW;    PERIODIC ARRAYS;    DYNAMIC PHASES;    SUPERCONDUCTORS;    VORTICES;    STATES;    FRUSTRATION;    TRANSITION;    MOTION;   

DOI  :  10.1103/PhysRevB.62.4096

来源: SCIE

【 摘 要 】

We study the dependence of the transport properties of square Josephson Junction arrays with the direction of the applied de current, both experimentally and numerically. We present computational simulations of current-voltage curves at finite temperatures for a single vortex in an array of LXL junctions (Ha(2)/Phi(0)=f = 1/L-2), and experimental measurements in 100x1000 arrays under a low magnetic field corresponding to f approximate to 0.02. We find that the transverse voltage vanishes only in the directions of maximum symmetry of the square lattice: the [10] and [01] direction (parallel bias) and the [11] direction (diagonal bias). For orientations different from the symmetry directions, we find a finite transverse voltage that depends strongly on the angle phi of the current. We find that vortex motion is pinned in the [10] direction (phi=0), meaning that the voltage response is insensitive to small changes in the orientation of the current near phi=0. We call this phenomenon orientational pinning. This leads to a finite transverse critical current for a bias at phi=0 and to a transverse voltage for a bias at phi not equal 0. On the other hand, for diagonal bias in the [11] direction the behavior is highly unstable against small variations of phi, leading to a rapid change from zero transverse voltage to a large transverse voltage within a few degrees. This last behavior is in good agreement with our measurements in arrays with a quasidiagonal current drive.

【 授权许可】

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