Pressure Dependence of the Structural Phase Transition Temperature in SrTiO₃and KMnF₃

Raman scattering spectra of ceramics, films, and superlattices of ferroelectric perovskites: A review

“…On the other hand, unlike the crystal, where the temperature T a , according to different authors, lies in the range from 105 to 110 K [31], for the ceramic samples, we have T a = 132 K. This shift in the transition temperature is most likely associated with the aforementioned internal stresses generated in the ceramic samples, because, as is known for the ST compound [32], the hydrostatic pressure leads to an increase in the temperature T a . Furthermore, even a small amount of calcium can also lead to an increase in T a [26].…”

Phase stability and shear softening inCaSiO3perovskite at high pressure

“…The tetragonal-cubic phase boundary in SrTiO 3 shows the same sense of curvature. 37 The negative slope of the tetragonal to orthorhombic boundary is caused by the larger volume of the low symmetry phase: while the orthorhombic phase shows rotations about two axes, as opposed to only one in the tetragonal phase, its volume is larger because the magnitude of rotation is less.…”

Structural Defects and the Origin of the Second Length Scale inSrTiO3

“…The elastic constants for SrTiO 3 at room temperature are C 11 316 GPa, C 12 102, and C 44 123 GPa (at 80 ϳ 300 K, the elastic constants vary by less than 8% [10,11]) with an anisotropy ratio A 2C 44 ͑͞C 11 2 C 12 ͒ 1.15, which suggests that the crystal is nearly isotropic. Based on the linear elasticity theory for isotropic solids [12], the trace of the stress tensor at a point ͑r, f͒ from an edge dislocation is…”