Magnetism of Higher Borides

Magnetism of borides which contain the $B_{12}$ icosahedra as a structural building block are attracting increasing interest since they exhibit unexpectedly strong magnetic interactions, despite being magnetically dilute f-electron insulators. The magnetic behavior among the different compounds has also been found to be diverse. The f-electron dependence of magnetic B_{12} icosahedra borides is compared, and found to be different from conventional mechanisms. The $TbB_{25}$ system is also investigated further and the transition is assigned to a typical antiferromagnetic transition.