Ferromagnetic ordering in the MMnF6 series (M = Ni, Cu, Zn, Pd)

Neutron diffraction experiments performed on MMnF6 compounds (M = Ni, Cu, Zn, Pd) have shown that both NiMnF6 and ZnMnF6 crystallize in the rombohedral R3 space group with a cationic ordering, whereas PdMnF6 shows cationic disordering (R3c, a = 5.46 Angstroem, α = 54.450). CuMnF6 has a monoclinic distortion derived from the MnF3 structural type (α = 8.57 Angstroem, b = 4.85 Angstroem, c = 13.46 Angstroem, β = 92.120). The magnetic properties can be correlated with the structure: the R3 ordered compounds show a fermomagnetic behavior (Tsub(c)(NiMnF6) = 39 K; Tsub(c)(ZnMnF6) = 9.5 K; Tsub(c)(CdMnF6) = 8 K), while the other two have an antiferromagnetic ordering. (orig.)