Anisotropic magnetic fluctuations in the ferromagnetic superconductor UCoGe studied by angle-resolved ^{59}Co NMR

TL;DR

This study uses angle-resolved ^{59}Co NMR to investigate the magnetic fluctuations in UCoGe, revealing strong Ising anisotropy and implications for spin-triplet superconductivity.

Contribution

It provides microscopic evidence of ferromagnetic anisotropy and discusses its role in the superconducting pairing mechanism in UCoGe.

Findings

Ferromagnetic static and dynamic susceptibilities with strong Ising anisotropy.

Superconductivity likely mediated by magnetic fluctuations favoring spin-triplet pairing.

Direction-dependent NMR measurements reveal anisotropic magnetic properties.

Abstract

We have carried out direction-dependent ^{59}Co NMR experiments on a single crystal sample of the ferromagnetic superconductor UCoGe in order to study the magnetic properties in the normal state. The Knight shift and nuclear spin-lattice relaxation rate measurements provide microscopic evidence that both static and dynamic susceptibilities are ferromagnetic with strong Ising anisotropy. We discuss that superconductivity induced by these magnetic fluctuations prefers spin-triplet pairing state.