Magnetic Phase Transitions in MII[N(CN)2]2

• Main Authors: Kmety, Carmen R., Manson, Jamie L., Huang, Qing-Zhen, Lynn, Jeffrey W., Erwin, Ross W., Miller, Joel S., Epstein, Arthur J.
• Format: Conference Proceeding
• Language: English
• Subjects: canted antiferromagnet; Condensed matter: electronic structure, electrical, magnetic, and optical properties; dicyanamide compounds; Exact sciences and technology; ferromagnet; Magnetic phase boundaries (including magnetic transitions, metamagnetism, etc.); Magnetic properties and materials; Magnetically ordered materials: other intrinsic properties; neutron powder diffraction; Physics; specific heat
• ISSN: 1058-725X
• DOI: 10.1080/10587259908023357

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 α-Co II [N(CN) 2 ] 2 (1a) and Ni II [N(CN) 2 ] 2 (2) are ferromagnets below T c , while β-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 1a exhibits an effective J′ = 1/2 behavior.