Abstract
The dynamics of texture formation, changes in crystal structure and stress accommodation
mechanisms are studied in R3c rhombohedral LaCoO3 perovskite during in-situ uniaxial
compression experiment by neutron diffraction. The neutron diffraction revealed the complex
crystallographic changes causing the texture formation and significant straining along certain
crystallographic directions during in-situ compression, which are responsible for the appearance
of hysteresis and non-linear ferroelastic deformation in LaCoO3 perovskite. The irreversible
strain after the first loading was connected with the appearance of non-recoverable changes in
the intensity ratio of certain crystallographic peaks, causing non-reversible texture formation.
However in the second loading/unloading cycle the hysteresis loop was closed and no irreversible strain appears after deformation. The significant texture formation is responsible for
increase in the Young’s modulus of LaCoO3 at high compressive loads, where the reported
values of Young’s modulus increase from 76 GPa measured at the very beginning of the loading
to 194 GPa at 900 MPa applied compressive stress measured at the beginning of the unloading
curve.
