Elastic properties of perovskiteYCrO3up to 60 GPa

Abstract

The high-pressure evolution of the ${\text{YCrO}}_{3}$ perovskite structure (space group $Pbnm$) has been investigated using synchrotron powder diffraction, up to 60 GPa. The results show an anisotropy in the elastic moduli of the individual crystallographic axes: the $b$ axis is appreciably less compressible than both $a$ and $c$ axes [${K}_{a0}=195(5)\text{ }\text{GPa}$, ${K}_{b0}=223(7)\text{ }\text{GPa}$, and ${K}_{c0}=200(6)\text{ }\text{GPa}$, respectively]. This implies that ${\text{YCrO}}_{3}$ becomes more distorted with increasing pressure, which is similar to what was previously found in ${\text{YTiO}}_{3}$ but opposite to the behavior reported for ${\text{YAlO}}_{3}$. Such contrasting trends are explained by the stronger confinement of Y ions in ${\text{YAlO}}_{3}$ due to the smaller size of octahedral network in the orthoaluminate compared to the orthochromate.