Observation of superconducting vortices carrying a temperature-dependent fraction of the flux quantum

Abstract

The magnetic response is a state-defining property of superconductors. The magnetic flux penetrates type-II bulk superconductors by forming quantum vortices when the enclosed magnetic flux is equal to the magnetic flux quantum. The flux quantum is the universal quantity that depends only on the ratio of fundamental constants: the electron charge and the Planck constant. This work investigates the vortex state in the hole-overdoped Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$ by using scanning superconducting quantum interference device (SQUID) magnetometry. We observed quantum vortices that carry only a fraction of the flux quantum, which vary continuously with temperature. This finding establishes the phenomenon that superconductors support quantum vortices with non-universally quantized magnetic flux. Furthermore, the demonstrations of the mobility of the fractional vortices and the manipulability of their positions open up a route for future fluxonics applications.

19 pages, 9 figures

References in corpus (6)

• Observation of half-height magnetization steps in Sr2RuO4
• Vortex Imaging in the pi-Band of Magnesium Diboride
• Magnetic response of mesoscopic superconducting rings with two order parameters
• A comprehensive scenario of the single crystal growth and doping dependence of resistivity and anisotropic upper critical fields in (Ba${}_{1-x}$K${}_x$)Fe${}_2$As${}_2$ ($0.22\le x\le 1$)
• Observation of superconducting vortices carrying a temperature-dependent fraction of the flux quantum
• The response of small SQUID pickup loops to magnetic fields

Cited by in corpus (6)

• Observation of superconducting vortices carrying a temperature-dependent fraction of the flux quantum
• Neutron Spin Resonance Near a Lifshitz Transition in Overdoped Ba${}_{0.4}$K${}_{0.6}$Fe${}_2$As${}_2$
• Atomic-scale Frustrated Josephson Coupling and Multi-condensate Visualization in FeSe
• Delocalization of vortex magnetic field near a planar defect
• Tuning Bound States of Symmetry-Breaking Vortices via Unidirectional Charge Density Wave in a Transition-Metal Dichalcogenide Superconductor
• Fractional vortex array realized at twin boundary in a nematic superconductor