Magnetic phase transitions in MII[N(CN)2]2

We summarize the magnetic behavior of M-II[N(CN)(2)](2) (M = Co, Ni, Mn and Zn). Analyses of the DC magnetization and AC susceptibility data demonstrate that alpha-Co-II[N(CN)(2)](2) (1a) and Ni-II[N(CN)(2)](2) (2) are ferromagnets below T-c, while beta-Co-II[N(CN)(2)](2) (1b) and Mn-II[N(CN)(2)](2) (3) are canted antiferromagnets below T-N. Zn-II[N(CN)(2)](2) (4) is diamagnetic. Specific heat and neutron powder diffraction results clearly define the transition temperatures for 1a, 1b, 2 and 3, Crystal structure determination from high-resolution neutron powder data for 1a, 2 and 3 shows that the three systems are isomorphous and crystallize in the orthorhombic space group Pnnm with Z = 2. Single crystal X-ray diffraction shows that 4 crystallizes in the orthorhombic space group Pnma with Z = 4. We solved the magnetic structures of 1a, 2 and 3 from neutron powder diffraction experiments. All low-temperature measurements are consistent with high-spin 1b, 2, 3 and 4, though la exhibits an effective J' = 1/2 behavior.