Influence of the annealing conditions on temperature-dependent ferroelastic behavior of LSCF

The macroscopic ferroelastic behavior of polycrystalline (La0.6Sr0.4)0.95Co0.2Fe0.8O3−δ and its dependence on annealing conditions was investigated over a temperature range from −150 °C to 150 °C. A temperature- and defect concentration-dependent variation of the ferroelastic behavior was attributed to internal stresses, oxygen deficiency, and a corresponding change of the crystal structure. In particular, there was an observed decrease in remanent strain and the formation of a closed ferroelastic hysteresis loop at temperatures below approximately 0 °C for samples annealed in air, which was suppressed through the reduction in oxygen vacancies by annealing the samples in oxygen. The macroscopic mechanical behavior as a function of annealing conditions is discussed with respect to the crystal structure and oxygen deficiency determined by means of x-ray and neutron diffraction. [Display omitted]