  Among the large class of Heusler compounds, Co2CrAl is predicted to be 100 %
spin polarized and is hence, a potential candidate for application in
spintronics. So far, the predicted properties have not been experimentally
realized which may be attributed to the phase segregated nature of samples.
This phase segregation is avoided using floating zone growth. However, the
grown sample was found to have undergone phase transformation via spinodal
decomposition at low temperatures. In the present work, thermal annealing has
been done on the spinodally decomposed samples and its effect on
microstructure, crystallographic structure and magnetic properties has been
studied. Annealing experiments were done and analyzed in order to understand
the extent of the solid state miscibility gap. With regards to the phase
diagram, the two-phase regime was found to extend till 1000 {\deg}C. Even at
1250 {\deg}C, we are still inside the immiscibility region. The thermodynamic
miscibility gap was thus found to exist until high temperatures and alternate
routes might be required to obtain a single phase sample with the desired high
spin polarization and Curie temperature in the Co-Cr-Al system.
