Observation of vortex coalescence in the anisotropic spin-triplet superconductor Sr$_{2}$RuO$_{4}$

TL;DR

This study uses scanning μSQUID microscopy to directly image magnetic flux structures in Sr₂RuO₄, revealing vortex behavior and flux domains that support the presence of unconventional chiral superconductivity.

Contribution

First direct imaging of vortex coalescence and flux domains in Sr₂RuO₄, providing evidence for intrinsic stabilization mechanisms linked to topological defects and chiral superconductivity.

Findings

Individual vortices observed at low fields

Flux domains form at intermediate fields

Evidence supports unconventional chiral superconductivity

Abstract

We present direct imaging of magnetic flux structures in the anisotropic, spin-triplet superconductor Sr$_{2}$RuO$_{4}$ using a scanning $\mu$SQUID microscope. Individual quantized vortices were seen at low magnetic fields. Coalescing vortices forming flux domains were revealed at intermediate fields. Based on our observations we suggest that a mechanism intrinsic to the material stabilizes the flux domains against the repulsive vortex-vortex interaction. Topological defects like domain walls can provide this, implying proof for unconventional chiral superconductivity.