Tailoring of the magnetic properties of SmCo/sub 5/:Nb/sub 0.33/Cr/sub 0.67/ nanocomposites using mechanical alloying

Nanocomposite structures composed of ferromagnetic particles dispersed in a matrix are systems in which the magnetic properties can be tailored by varying the size and spacing of the ferromagnetic particles. Nanocomposites of SmCo/sub 5/ in a non-magnetic Nb/sub 0.33/Cr/sub 0.67/ matrix exhibit a wide variety of magnetic properties. SmCo/sub 5/ powder is premilled prior to mechanical alloying. The premilling results in a maximum coercivity of 16 kOe after 2 hours of milling, and an enhanced remanence ratio. Both features may be due to exchange anisotropy and/or exchange coupling between hard and soft ferromagnetic phases. The nanocomposite samples show that, when the SmCo/sub 5/ particulates are small enough, the primary effect of alloying is to disperse them throughout the matrix with no further refinement of size.