ABSTRACT
Two new cation-ordered polymorphs of Mn2ScSbO6 have been synthesised at high-pressure. At 5.5 GPa and 1523 K Mn2ScSbO6 crystallizes in the Ni3TeO6-type structure with the polar R3 space group and cell parameters a = 5.3419 (5) Å and c = 14.0603 (2) Å. Below TC = 42.0 K it exhibits ferrimagnetic order with a net magnetization of 0.6µB arising from unusual site-selective Mn/Sc disorder and is thus a potential multiferroic material. A double perovskite phase obtained at 12 GPa and 1473 K crystallizes in the non-polar P21/n monoclinic space group with cell parameters a = 5.2909 (3) Å, b = 5.4698 (3) Å, c = 7.7349 (5) Å and ß = 90.165 (6) °. Magnetization and neutron diffraction experiments reveal antiferromagnetic order below TN = 22.3 K with the spins lying in the ac plane.
ABSTRACT
The perovskite form of the Mn2FeSbO6 oxide has been obtained at 5.5 GPa and 1523 K. X-ray and neutron diffraction data reveal that this compound crystallizes in the monoclinic P21/n space group with a = 0.5234 nm, b = 0.5389 nm, c = 0.7642 nm and ß = 90.372° lattice parameters. AC and DC magnetic susceptibility measurements suggest the existence of a complex magnetic behavior below 200 K. The magnetic structure has been determined and can be described on the basis of an elliptical spiral with an incommensurate propagation vector, k = [0,0.426,0], where the magnetic moments of 2Mn(2+) and Fe(3+) cations are confined to the ac-plane.
