Anisotropic decomposition ofHe3-He4mixtures

The late stage of phase separation in ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-${}_{}{}^4{}_{}{}^{}\mathrm{He}$ mixtures, quenched into the miscibility gap below the tricritical point, has been studied by light scattering. The scaled structure factor $F\left(\frac{k}{k_m}\right)$, which in general exhibits a universal shape, becomes nonuniversal as a pronounced vertical-horizontal asymmetry of the scattered intensity appears. This result indicates the influence of gravity on the decomposition process at that stage.