Two-dimensional incommensurate magnetic fluctuations in Sr$_2$(Ru$_{0.99}$Ti$_{0.01}$)O$_4$

TL;DR

This study uses neutron scattering to analyze incommensurate magnetic fluctuations in Ti-doped Sr$_2$RuO$_4$, revealing temperature-dependent behavior consistent with Fermi liquid theory and showing suppression of magnetic fluctuations due to Ti doping.

Contribution

It provides detailed characterization of magnetic fluctuations in Ti-doped Sr$_2$RuO$_4$ and compares them with the parent compound, highlighting doping effects on magnetic excitations.

Findings

Incommensurate magnetic fluctuations are observed around Q=(0.3,0.3,L).

Fluctuations are well described by a Fermi liquid response below 50 K.

Ti doping suppresses magnetic fluctuations compared to the parent compound.

Abstract

We investigate the imaginary part of the wave vector dependent dynamic spin susceptibility in Sr$_2$(Ru$_{0.99}$Ti$_{0.01}$)O$_4$ as a function of temperature using neutron scattering. At T=5 K, two-dimensional incommensurate (IC) magnetic fluctuations are clearly observed around $\mathbf{Q}_\text{c}=(0.3,0.3,L)$ up to approximately 60 meV energy transfer. We find that the IC excitations disperse to ridges around the $(\pi,\pi)$ point. Below 50 K, the energy and temperature dependent excitations are well described by the phenomenological response function for a Fermi liquid system with a characteristic energy of 4.0(1) meV. Although the wave vector dependence of the IC magnetic fluctuations in Sr$_2$(Ru$_{0.99}$Ti$_{0.01}$)O$_4$ is similar to that in the Fermi liquid state of the parent compound, Sr$_2$RuO$_4$, the magnetic fluctuations are clearly suppressed by the Ti-doping.