Anisotropic response of the moving vortex lattice in superconducting Mo$_{(1-x)}$Ge$_{x}$ amorphous films

TL;DR

This study investigates the anisotropic behavior of vortex responses in amorphous MoGe superconducting films, revealing directional dependence in vortex dynamics related to the peak effect in critical current.

Contribution

It demonstrates the anisotropic vortex response in MoGe films and links it to the peak effect, providing new insights into vortex dynamics in amorphous superconductors.

Findings

Anisotropic vortex response observed in a specific phase diagram region.

Reduced shielding effectiveness along vortex motion direction.

Isotropic behavior recovered at higher temperatures.

Abstract

We have performed magnetic susceptibility measurements in Mo$_{(1-x)}$Ge$_x$ amorphous thin films biased with an electrical current using anisotropic coils. We tested the symmetry of the vortex response changing the relative orientation between the bias current and the susceptibility coils. We found a region in the DC current - temperature phase diagram where the dynamical vortex structures behave anisotropically. In this region the shielding capability of the superconducting currents measured by the susceptibility coils is less effective along the direction of vortex motion compared to the transverse direction. This anisotropic response is found in the same region where the peak effect in the critical current is developed. On rising temperature the isotropic behavior is recovered.