Hole concentration dependence of the ordering process of the stripe order in La2-xSrxNiO4

Ordering process of stripe order in ${\mathrm{La}}_{2-x}{\mathrm{Sr}}_x{\mathrm{NiO}}_4$ with x being around 1/3 was investigated by neutron-diffraction experiments. When the stripe order is formed at high temperature, incommensurability $\epsilon$ of the stripe order has a tendency to show the value close to 1/3 for the samples with x at both sides of 1/3. With decreasing temperature, however, $\epsilon$ becomes close to the value determined by the linear relation of $\epsilon {=n}_h,$ where $n_h$ is a hole concentration. This variation of the $\epsilon$ strongly affects the character of the stripe order through the change of the carrier densities in stripes and antiferromagnetic domains.