  We study the order-disorder transition in colloidal suspensions under shear
flow by performing Brownian dynamics simulations. We characterize the
transition in terms of a statistical property of time-dependent maximum value
of the structure factor. We find that its power spectrum exhibits the power-law
behaviour only in the ordered phase. The power-law exponent is approximately -2
at frequencies greater than the magnitude of the shear rate, while the power
spectrum exhibits the $1 / f$-type fluctuations in the lower frequency regime.
