Detailed magnetic studies on Co(N3)2(4-acetylpyridine)2: a weak-ferromagnet with a very big canting angle.
The magnetic properties of Co(N 3) 2(4acpy) 2 have been thoroughly reexamined on both powder and well-oriented single crystal samples. This azido-bridged cobalt compound of (4, 4) layer shows a weak-ferromagnetic state below T C = 11.2 K. The magnetic axes were determined to be along the crystallographic a*, b, and c axes for the monoclinic space group P2 1/c. The easy axis lies along the b-axis, the canting is along the a*-axis, and the hard axis is along the c-axis. Strong anisotropy due to the oriented moments in the ordered state and/or the single-ion anisotropy of Co (2+) exists in the whole temperature range from 2 to 300 K. Below T C, very big spontaneous magnetization was observed and was attributed to the very big canting angle (15 degrees at 2 K). A possible spin configuration was then proposed to explain the experimental results. The origin of the big spin canting was discussed, and a weak-ferromagnetic approach toward molecular magnets with big spontaneous magnetization was proposed accordingly.
Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, PR China.
Xin-Yi
XY
Wang
Zhe-Ming
ZM
Wang
Song
S
Gao