Thermodynamic approach to experimental research of functional crystalline materials

The functional properties of crystals have been described by the thermodynamics potential of a crystal. This potential usually is presented as matrix, the elements of which represent physical properties of crystals. Using the partial derivatives we can obtain some physical properties of crystals. In the experimental part of article the results of study of some functional properties of a ferroelastic monocrystal of molybdate (III) gadolinium (VI) are presented.