  Thermodynamic properties of the mixed spin-3/2 and spin-1/2 Heisenberg model
are examined within the Oguchi approximation in the presence of a random
crystal-field (RCF). The RCF is either introduced with probability p or turned
off with probability 1-p randomly. The thermal variations of the global
magnetization and free energy of the system are investigated to construct the
phase diagrams for the classical, quantum and anisotropic cases. Different
results revealed that no qualitative changes exist between them. Quantum
effects are found to be present and abundant in the quantum model in the
negative D -range. This phenomenon has a strong decreasing effect on the
critical temperature which becomes much lower than in the classical case. In
the presence of an external field, it was observed that coercivity and
remanence decrease in a wide range of the absolute temperature.
