Crystal Growth and Magnetic Properties of Lanthanide-Containing Osmium Double Perovskites, Ln₂NaOsO₆ (Ln = La, Pr, Nd)

A series of double perovskite oxides, Ln2NaOsO6 (Ln = La, Pr, Nd), has been prepared as single crystals from acidic molten NaOH. All three oxides crystallize in the monoclinic space group P21/n (Glazer tilt system #10, a-a-b+), forming a 1:1 ordered rock salt lattice of the Na+ and Os5+ cations. Magnetic susceptibility measurements show evidence of antiferromagnetic correlations in La2NaOsO6 and of a spin-flop transition from an antiferromagnetic to ferromagnetic-like state in both Pr2NaOsO6 and Nd2NaOsO6.