A neutron scattering study of the mixed state of Yb$_{3}$Rh$_{4}$Sn$_{13}$

TL;DR

This study uses small angle neutron scattering to analyze the vortex lattice in Yb₃Rh₄Sn₁₃, revealing a single domain, distorted hexagonal vortex structure with field-dependent rotation and symmetry, characteristic of a strongly type-II superconductor.

Contribution

First detailed neutron scattering investigation of the vortex lattice in Yb₃Rh₄Sn₁₃, showing unique field and orientation-dependent vortex arrangements and symmetry preferences.

Findings

Vortex lattice is a single domain with distorted hexagonal geometry.

In-plane rotation of vortex lattice observed with different field directions.

Superconductor characterized by isotropic gap, λ_L = 2508 Å, ξ = 100 Å, and κ = 25.

Abstract

Using the small angle neutron scattering (SANS) technique we investigated the vortex lattice (VL) in the mixed state of the stannide superconductor Yb$_{3}$Rh$_{4}$Sn$_{13}$. We find a single domain VL of slightly distorted hexagonal geometry for field strengths between 350 and 18500 G and temperatures between T = 0.05 and T = 6.5 K. We observe a clear in-plane rotation of the VL for different magnetic field directions relative to the crystallographic axes. We also find that the hexagonal symmetry of the VL is energetically favorable in Yb$_{3}$Rh$_{4}$Sn$_{13}$ for external fields oriented along axes of different symmetries: twofold [110], threefold [111] and fourfold [100]. The observed behavior is different from other conventional and unconventional superconductors. The superconducting state is characterized by an isotropic gapped order parameter with an amplitude of $\Delta(0)$ = 1.57 $\pm$ 0.05 meV. At the lowest temperatures the field dependence of the magnetic form factor in our material reveals a London penetration depth of $\lambda_{L}$ = 2508 $\pm$ 17 $\AA$ and a Ginzburg coherence length of $\xi$ = 100 $\pm$ 1.3 $\AA$, i.e., it is a strongly type-II superconductor, $\kappa$ = $\lambda_{L}/\xi$ = 25.