Long range Néel order in the quasi-one-dimensional vanadium-based(S=1)pyroxenes(Li,Na)V(Si,Ge)2O6

Abstract

The long range N\'eel order formation in quasi-one-dimensional vanadium-based $(S=1)$ chain compounds with pyroxenes structure $(\mathrm{Li},\mathrm{Na})\mathrm{V}{(\mathrm{Si},\mathrm{Ge})}_{2}{\mathrm{O}}_{6}$ has been established at low temperatures. The main parameters of the magnetic subsystem of these compounds were estimated through the measurement of specific heat and magnetic susceptibility. The temperature distribution of magnetic entropy released at short range and long range magnetic ordering was found through comparison with isostructural nonmagnetic Sc-based pyroxenes $(\mathrm{Li},\mathrm{Na})\mathrm{Sc}{(\mathrm{Si},\mathrm{Ge})}_{2}{\mathrm{O}}_{6}$. At substitution of Na for Li and Ge for Si, the systematic enlargement of intrachain exchange interaction parameter ${\mathbf{J}}_{\ensuremath{\Vert}}$ as compared to interchain exchange interaction parameter ${\mathbf{J}}_{\ensuremath{\perp}}$ results in increasing ``one dimensionality'' in this family of complex metaloxides.