The existence of a stripe-liquid phase in a layered nickelate, ${\mathrm{La}}_{1.725}{\mathrm{Sr}}_{0.275}{\mathrm{NiO}}_4$, is demonstrated through neutron scattering measurements. We show that incommensurate magnetic fluctuations evolve continuously through the charge-ordering temperature, although an abrupt decrease in the effective damping energy is observed on cooling through the transition. The energy and momentum dependence of the magnetic scattering are parametrized with a damped-harmonic-oscillator model describing overdamped spin waves in the antiferromagnetic domains defined instantaneously by charge stripes.

• Received 11 October 2001

DOI:https://doi.org/10.1103/PhysRevLett.88.126401