Incommensurate Magnetic Ordering in ${\mathrm{Sr}}_2{\mathrm{Ru}}_{1-\mathit{x}}{\mathrm{Ti}}_{\mathit{x}}{O}_4$

In ${\mathrm{Sr}}_2{\mathrm{RuO}}_4$ the spin excitation spectrum is dominated by incommensurate fluctuations at $\mathbf{q}=\left(0.30{.3q}_z\right)$, which arise from Fermi-surface nesting. We show that upon Ti substitution, known to suppress superconductivity, a short range magnetic order develops with a propagation vector (0.307 0.307 1). In ${\mathrm{Sr}}_2{\mathrm{Ru}}_{0.91}{\mathrm{Ti}}_{0.09}{\mathrm{O}}_4$, the ordered moment points along the $c$ direction. This finding shows that superconducting ${\mathrm{Sr}}_2{\mathrm{RuO}}_4$ is extremely close to an incommensurate spin density wave instability.