RESUMO
The crystal structure of the Ni0.5TiSe2 compound has been studied in situ in the temperature range of 25-1000 °C using synchrotron radiation X-ray diffraction. The previously known order-disorder transition in the Ni sublattice at â¼100 °C was found to be a second-order phase transition and belongs to the 3D Ising universality class. Reversible extraction of nickel selenides was observed in the temperature range of 275-975 °C. It was explained in terms of Ni extraction from Ni0.5TiSe2 due to the thermal widening of the Ni 3d/Ti 3d/Se 4p impurity band. The Ni-TiSe2 phase diagram follows the typical pattern of MxTiSe2 (M - transition metal) compounds.
RESUMO
The effect of atomic ordering in the cobalt sublattice on the electronic structure of the CoxTiSe2 intercalation compounds has been studied using a complex of spectral techniques - XPS, XAS, and ResPES, along with theoretical calculations of the total and partial densities of states. It has been found that the cobalt intercalation significantly affects the character of the chemical bond inside the host lattice. No signs of the direct overlapping of the Co 3d orbitals in the ordered material were observed. It has been found that the reason for the ordering of the cobalt atoms is a Co 3d/Ti 3d/Se 4p hybridization.
