Time and frequency dependent mechanical properties of LaCoO_3-based perovskites: Neutron diffraction and domain mobility

摘要

The study of domain wall movement and texture formation in ferroelastic LaCoO3 perovskite under constant applied compressive stress has been performed using in situ neutron diffraction. It was established that under constant applied compressive stress the domain walls show mobility that may lead both to the shrinkage (creep strain) and to the expansion (negative creep strain) of LaCoO3 perovskite. The domain wall movement and texture formation can be explained by the availability, mobility, and interaction of twins, stacking faults, antiphase boundaries, dislocations, and point defects, such as oxygen vacancies and their complexes as well as impurity atoms. The equation of motion was used to describe the possible mechanisms of domain wall movement under applied stress, and it was determined that the available solutions of this equation allow both for the shrinkage (creep strain) and for the expansion (negative creep strain) of LaCoO3 perovskite to occur. Published by AIP Publishing.