Direct observation of vortex liquid droplets in the iron pnictide superconductor CaKAs${}_4$Fe${}_4$ at $0.5T$_c$

Oscar Bou Marqués, Jose A. Moreno, Pablo García Talavera +7

Type-II superconductors under magnetic fields are in a quantum coherent non-dissipative state as long as vortices remain pinned. Dissipation appears when vortices depin, eventually…