Observation of a gel of quantum vortices in a superconductor at very low magnetic fields

LLORENS, JOSÉ BENITO; EMBON, LIOR; CORREA, ALEXANDRE; GONZÁLEZ, JESÚS DAVID; HERRERA, EDWIN; GUILLAMÓN, ISABEL; LUCCAS, ROBERTO F.; AZPEITIA, JON; MOMPEÁN, FEDERICO J.; GARCIÁ-HERNÁNDEZ, MAR; MUNUERA, CARMEN; SÁNCHEZ, JAZMÍN ARAGÓN; FASANO, YANINA; MILOEVI?, MILORAD V.; SUDEROW, HERMANN; ANAHORY, YONATHAN

Physical Review Research

American Physical Society

Lugar: College Park; Año: 2020 vol. 2 p. 13329 - 13329

2643-1564

A gel consists of a network of particles or molecules formed for example using the sol-gel process, by which a solution transforms into a porous solid. Particles or molecules in a gel are mainly organized on a scaffold that makes up a porous system. Quantized vortices in type-II superconductors mostly form spatially homogeneous ordered or amorphous solids. Here we present high-resolution imaging of the vortex lattice displaying dense vortex clusters separated by sparse or entirely vortex-free regions in β-Bi2Pd superconductor. We find that the intervortex distance diverges upon decreasing the magnetic field and that vortex lattice images follow a multifractal behavior. These properties, characteristic of gels, establish the presence of a novel vortex distribution, distinctly different from the well-studied disordered and glassy phases observed in high-temperature and conventional superconductors. The observed behavior is caused by a scaffold of one-dimensional structural defects with enhanced stress close to the defects. The vortex gel might often occur in type-II superconductors at low magnetic fields. Such vortex distributions should allow to considerably simplify control over vortex positions and manipulation of quantum vortex states.