Effect of vacancy ordering on magnetic susceptibility of tantalum carbide

Ordering of carbon atoms and vacancies in nonmetallic sublattice of nonstoichiometric tantalum carbide TaCy is studied by the methods of magnetic susceptibility and structural neutron diffraction analysis. Ordering in tantalum carbide is established to be accompanied by decrease of its magnetic susceptibility. The presence of hystheresis in temperature dependences of magnetic susceptibility (300-1300 K) of ordered tantalum carbide, as well as structural data on neutron diffraction analysis obtained permit to consider that ordering in TaCy occur as the phase first-order transition