High-resolution dilatometry measurements ofSrTiO3salong cubic and tetragonal axes

High-resolution dilatometry measurements have been made for ${\mathrm{SrTiO}}_3$ along the tetragonal-phase a and c axes and the cubic-phase [100] direction between 2 and 280 K. A moderate stress field was used to align the domains of the low-temperature tetragonal phase or to force a single domain. Anisotropy in the thermal strain at temperatures above the cubic to tetragonal transformation has been observed in the cubic phase for the measurements along the a and c directions. No structural change or strain anomaly has been detected at ∼37 K, the proposed transition temperature to the quantum-paraelectric regime. The expansion of the tetragonal c axis with decrease of temperature is arrested below 10 K. The implications of the observed anomalies are discussed.