FEATURES OF CRYSTAL AND MAGNETIC STRUCTURES OF LAYERED COMPOUNDS CoxTiS2 (0 < x ≤ 1.00)

Abstract

The crystal structure data of Co_xTiS₂ series of compounds in a wide range of Co concentrations(0.00 < x ≤ 1.00) are summarized. The compounds with high cobalt concentrations (x ≥ 0.75) have been synthesized for the first time. The $P\bar{3}m1$ space group was found to be typical for the compounds with low (x < 0.2) and high (x ≥ 0.75) Co concentrations, while the compounds with intermediate Co concentrations show different types of ordered structures. The lattice contraction with increasing x up to x = 0.5 is in good agreement with the electromotive force measurements in the Li|Li⁺|Co_xTiS₂ electrochemical cell. The magnetic properties of Co_xTiS₂ strongly depend on the Co content: the spin glass ordering at low (T < 50 K) temperatures, typical for x < 0.25, changes to the ferromagnetic one for 0.75 ≤ x ≤ 1.00, which is preserved even at high (T > 900 K) temperatures.