Crystal preparation, structures, and magnetic properties of layer-type Cs4B3F10 compounds (B = Fe, Co, Ni)
Abstract
Cs4B3F10-type compounds are found in systems where B=Fe, Co, Ni, Mg, and Zn. Structurally, they can be considered as consisting of units of three face-shared BF6 octahedra (B 3F12 groups) which are connected to each other by corner sharing to form layers consisting of linked B3F12 groups. The layers are separated by the large Cs+ ions and exhibit mica-like cleavage along this plane. Structures of this type usually have intraplane magnetic interactions which are markedly stronger than those between planes. Our magnetic results show Cs4Fe3F10 to be an antiferromagnet with TN∼22°K, while the Co and Ni compounds have a more complicated magnetic order with TN's of 33° and 15°K, respectively. Their magnetizations at 4.2°K are 16 and 1.0 emu/g and the easy directions are parallel to the cleavage plane. The structure does not allow a simple superexchange between B ions of neighboring planes. A more involved interaction involving the Cs+ ions and enhanced by the intraplane ordering is likely. Large anisotropy of the paramagnetic susceptibilities of the cobalt and nickel compounds was observed. © 1971 The American Institute of Physics.