Vortex Transport Interference Transitions

Abstract

Interference transitions are observed in the mixed state of a superconducting, oxygen-doped, aluminum film* when flux flow is driven by applied collinear rf and dc electric transport currents.1 In this study particular attention is paid to the rf resistivity p' for rf current amplitudes small compared to the dc current. Under these conditions p' is independent of the rf current, and as a function of the dc electric field exhibits a series of steplike transitions such as those shown in Fig. 1. Transitions occur for values of the dc flow velocity v, which is proportional to the dc field, that satisfy the relation $$2\pi f=\left| v\cdot g \right|$$ (1) where f is the frequency of the rf current and g is a vector of the reciprocal vortex lattice. The orientation of the lattice is such that we can write $$\left| v\cdot g \right|=\frac{1}{2}\sqrt{3}nv{{g}_{1}}$$ (2) where g 1 is the reciprocal lattice constant and n is an integer. Thus, the nth transition step corresponds to reciprocal lattice points along rows perpendicular to v that satisfy Eq. (2).