A composite material comprising randomly distributed spherical particles of
two different isotropic dielectric-magnetic materials is homogenized using the
second-order strong-property-fluctuation theory in the long-wavelength
approximation. Whereas neither of the two constituent materials by itself
supports planewave propagation with negative phase velocity (NPV), the
homogenized composite material (HCM) can. The propensity of the HCM to support
NPV propagation is sensitive to the distributional statistics of the
constituent material particles, as characterized by a two--point covariance
function and its associated correlation length. The scope for NPV propagation
diminishes as the correlation length increases