Vortex imaging in amorphous Mo80Ge20 pentagons

Highlights: •Direct observation of vortex configuration in Mo80Ge20 pentagons using the scanning SQUID microscope. •Vortex distribution in pentagon tends to adapt one of five symmetric axes of pentagon. •The rule of shell filling will be altered when the size of the pentagon is different. -- Abstract: We present the direct observation of vortex configuration in Mo80Ge20 pentagons using the scanning SQUID microscope. Systematic measurements allow us to reveal how vortices are confined in a restricted sample as well as how vortex arrangement evolves with increasing the applied magnetic field. Vortex distribution in pentagon tends to take one of five symmetric axes of pentagon expected from sample geometry. We found that the rule of shell filling is different among various different sizes of the pentagons. For vorticity of six, vortices form a two-shell structure in small pentagon, while single shell structure in larger pentagon. We also demonstrate that the vortex dragging effect can be caused by the superconducting pick-up coil in a weak pinning specimen