# Absence of a large superconductivity-induced gap in magnetic fluctuations of Sr2RuO4

## TL;DR

This study uses inelastic neutron scattering to investigate magnetic fluctuations in Sr2RuO4 across its superconducting transition, finding no large superconductivity-induced gap in magnetic spectral weight at energies above 0.3 meV.

## Contribution

It provides direct experimental evidence that the nesting-induced magnetic fluctuations in Sr2RuO4 do not develop a large gap in the superconducting state, challenging certain pairing models.

## Key findings

- No observable change in magnetic fluctuations at energies down to ~0.35 meV across T_c.
- Magnetic fluctuations persist in the superconducting state at energies above 0.3 meV.
- Partial suppression of spectral weight occurs below ~0.3 meV in the superconducting state.

## Abstract

Inelastic neutron scattering experiments on Sr2RuO4 determine the spectral weight of the nesting induced magnetic fluctuations across the superconducting transition. There is no observable change at the superconducting transition down to an energy of ~0.35 meV, which is well below the 2 delta values reported in several tunneling experiments. At this and higher energies magnetic fluctuations clearly persist in the superconducting state. Only at energies below ~0.3 meV evidence for partial suppression of spectral weight in the superconducting state can be observed. This strongly suggests that the one-dimensional bands with the associated nesting fluctuations do not form the active, highly gapped bands in the superconducting pairing in Sr2RuO4.