Calculation of a temperature-concentration phase diagram of mixed LiK1-xRbxSO4 crystals

We study here the temperature-concentration (T-X) phase diagram of mixed LiK(1-x)Rb(x)SO(4) crystals obtained using a mean field model. We expand the free energies of phases II, III, IV, and V in terms of the order parameters and calculate the phase line equations for the II-III, III-IV, and IV-V transitions in this crystal. By fitting our phase line equations to the experimental data, we obtain a T-X phase diagram of mixed LiK(1-x)Rb(x)SO(4) crystals. Using the phase line equations derived from our mean field model given here, the observed behaviour of some thermodynamic quantities can be predicted in the temperature and concentration ranges studied for the phases II, III, IV, and V in mixed LiK(1-x)Rb(x)SO(4) crystals.