Hierarchical Assembly of Sm_2Co_7/Co Magnetic Nanoparticles into Highly Stable and Uniform Nanospheres

摘要

Hierarchical assembly of colloidal Sm_2Co_7/Co clusters in the form of nanospheres has been processed through a polyol process. The SmCo nanospheres are found to be robust, uniform (～100 nm) and tend to self-assemble in the form of ordered superstructures. Each nanosphere consists of large number of discrete fine particles (～6.0 nm), having two-phase structure of both Sm_2Co_7 and Co-phases. Upon annealing, these phases transform into Sm_2Co_(17) phase with very high magnetization (169 emu/g). A possible mechanism on the formation of nanospheres from the individual Sm_2Co_7 and Co nanoparticles is also discussed.