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Free keywords:
rubidium manganate; azide/nitrate route; crystal structure; magnetic properties
Abstract:
RbMnO2 was prepared via the azide/nitrate route. Stoichiometric mixtures of the precursers (Mn2O3, RbN3 and RbNO3) were heated in a special regime up to 600 C and annealed at this temperature for 30 h in specially designed silver crucibles. Single crystals have been grown by annealing a 1:1 mixture of Rb2O and MnOx at 585 C for 1200 h. According to the crystal structure determination Mn3+ is in a square-pyramidal coordination by oxygen. These [MnO5] units form double chains extending along the crystallographic c-axis. RbMnO2 shows Curie-Weiss behaviour down to similar to 100 K. A fit of the susceptibility data yields an average value of the magnetic moment (per manganese atom) of mu(eff) = 5.33 mu(B), and theta(P) = -820 K. At 50 K and low field strength onset of ferromagnetic order due to spin canting has been observed.
