Magnetostriction and low temperature crystal structure evolution of the highly distorted perovskites SeNi1-xCoxO3 using high-resolution sync

The main goal of this proposal is to investigate low temperature crystal structure evolution across the Néel Temperature (TN) and some magnetic features observed from magnetic susceptibility for the Se(Ni1-xCox)O3 (x = 0, 0.1, 0.2, 0.4, 0.6 and 0.8) perovskites, using the state-of-art high-resolution synchrotron x-ray diffractometer available at the beamline ID22, ESRF. These are the most distorted perovskites, characterized by a huge tilting of the Ni(Co)O6 octahedra, due to the stereochemical effect of the lone electron pair of Se(IV). They must be prepared uinder high-pressure conditions. The main questions to be addressed are the followings: (i) What is the correlation between the crystal structure evolution across the magnetic ordering temperature and the spin configuration at long-range, and (ii) how such a correlation evolves for the different members of the series from SeNiO3 to SeCoO3?