  Longitudinal-field muon-spin-relaxation measurements have revealed
inhomogeneous distribution of the internal magnetic field at temperatures above
the bulk superconducting (SC) transition temperature, $T_{\rm c}$, in slightly
overdoped Bi$_2$Sr$_2$Ca$_{1-x}$Y$_x$Cu$_2$O$_{8+\delta}$. The distribution
width of the internal magnetic field, $\Delta$, evolves continuously with
decreasing temperature toward $T_{\rm c}$. The origin of the increase in
$\Delta$ is discussed in terms of the creation of SC domains in a sample.
