  Shear localization in an aqueous clay suspension of Laponite is investigated
through dynamic light scattering, which provides access both to the dynamics of
the system (homodyne mode) and to the local velocity profile (heterodyne mode).
When the shear bands form, a relaxation of the dynamics typical of a gel phase
is observed in the unsheared band soon after flow stop, suggesting that an
arrested dynamics is present during the shear localization regime. Periodic
oscillations of the flow behavior, typical of a stick-slip phenomenon, are also
observed when shear localization occurs. Both results are discussed in the
light of various theoretical models for soft glassy materials.
