  We present the results of low temperature (LT) annealing studies of
Ga1-xMnxAs epilayers grown by low temperature molecular beam epitaxy in a wide
range of Mn concentrations (0.01<x<0.084). Transport measurements in low and
high magnetic fields as well as SQUID measurements were performed on a wide
range of samples, serving to establish optimal conditions of annealing. Optimal
annealing procedure succeeded in the Curie temperatures higher than 110K. The
highest value of Curie temperature estimated from the maximum in the
temperature dependence of zero-field resistivity (Tr) was 127K. It is generally
observed that annealing leads to large changes in the magnetic and transport
properties of GaMnAs in the very narrow range of annealing temperature close to
the growth temperature.
