Domain distribution below the cubic-to-tetragonal phase transition in RbCaF3under biaxial stress

The domain-volume distribution as a function of temperature has been determined in the tetragonal phase of RbCa${\mathrm{F}}_3$ below $T_0=198\mathrm{}$ K with the use of neutron diffraction from differently shaped large single crystals. The data show good agreement with x-ray experiments. The domain-volume distribution was manipulated by the application of biaxial stress on the single crystal in order to generate a single domain below $T_0$. We achieved a more than 91% single domain with a moderate stress $\sigma =11.8\mathrm{}$ bar. Temperature and stress hysteresis were investigated. We also observed a change in the central component of the cubic phase. Precursor effects are seen.