  The symmetry energy and the isoscaling properties of the fragments produced
in the multifragmentation of $^{40}$Ar, $^{40}$Ca + $^{58}$Fe, $^{58}$Ni
reactions at 25 - 53 MeV/nucleon were investigated within the framework of
statistical multifragmentation model. The isoscaling parameters $\alpha$, from
the primary (hot) and secondary (cold) fragment yield distributions, were
studied as a function of excitation energy, isospin (neutron-to-proton
asymmetry) and fragment symmetry energy. It is observed that the isoscaling
parameter $\alpha$ decreases with increasing excitation energy and decreasing
symmetry energy. The parameter $\alpha$ is also observed to increase with
increasing difference in the isospin of the fragmenting system. The sequential
decay of the primary fragments into secondary fragments, when studied as a
function of excitation energy and isospin of the fragmenting system, show very
little influence on the isoscaling parameter. The symmetry energy however, has
a strong influence on the isospin properties of the hot fragments. The
experimentally observed scaling parameters can be explained by symmetry energy
that is significantly lower than that for the ground state nuclei near
saturation density. The results indicate that the properties of hot nuclei at
excitation energies, densities and isospin away from the normal ground state
nuclei could be significantly different.
