Cobalt nanocrystallites encapsulated in boron nitride shells

Co nanocrystallites were encapsulated in boron nitride closed shells using a one-step simple chemical method, the decomposition of amine complex in the presence of KBH4 and nitrogen atmosphere at 1000 °C. Magnetic measurements determined a value of the saturation magnetization of 72 emu/g and a weak ferromagnetic behavior, with a coercivity of 82 Oë. Synchrotron X-ray diffraction combined with Rietveld analysis demonstrated that type σII residual stresses of up to ∼2 GPa were present in the encapsulated Co nanocrystallites. We observed an interesting decrease in Bragg reflection half-width with increasing order of reflection, observed previously only in another fcc-metal nanosized material, a ∼5 nm polycrystalline Ni.