Thermal Expansion of SrF2 at Elevated Temperatures

Abstract
The X‐ray method was used to determine the linear thermal expansion coefficient of SrF2 in the temperature range from 301 to 1173 K. A comparison of the thermal expansion coefficients of CaF2, SrF2 and BaF2 at T > 300 K shows that the degree of lattice an–harmonicity in the alkaline earth fluorides decreases with increasing mass of the alkaline earth atom. The results for the thermal expansion of SrF2 are used to discuss the temperature dependence of the lattice mismatch in the SrF2/InP film–substrate system.