  We have for the first time experimentally investigated the weak localisation
magnetoresistance in a AlGaAs/GaAs p-type quantum well. The peculiarity of such
systems is that spin-orbit interaction is strong. On the theoretical side it is
not possible to treat the spin-orbit interaction as a perturbation. This is in
contrast to all prior investigations of weak localisation. In this letter we
compare the experimental results with a newly developed diffusion theory, which
explicitly describes the weak localisation regime when the spin-orbit coupling
is strong. The spin relaxation rates calculated from the fitting parameters was
found to agree with theoretical expectations. Furthermore the fitting
parameters indicate an enhanced phase breaking rate compared to theoretical
predictions.
