Martensitic and Superconducting Transitions in In-Tl Alloy

In-Tl alloy undergoes a martensitic transformation from f.c.c. to f.c.t. and becomes a superconductor below about 3.4 K. These transitions are treated by a phenomenological theory based on the Landau's theory of phase transition. Temperature dependence of spontaneous strain ( c / a -1 of f.c.t. phase), elastic constant (C 11 –C 12 )/2, and composition dependence of martensitic and superconducting transition temperatures are calculated. A good agreement with the experiment is obtained.