Crystal structure and magnetic properties of ultrafine nanocrystalline SmCo3 compound.

The single-phase ultrafine nanocrystalline SmCo(3) compound with a high coercivity of 33 kOe and a Curie temperature of 925 K was prepared using a simple and efficient method, which took advantages of the concurrent processes of nanocrystallization and densification during spark plasma sintering. The crystal structure of the nanocrystalline SmCo(3) compound was constructed. As compared with the conventional microcrystalline SmCo(3) compound, a large axial ratio c/a = 4.920 and an expansion of the unit cell volume of 2.97% were obtained in the lattice structure of the nanocrystalline SmCo(3). The relationship between the magnetic properties and the nanocrystalline structure was analyzed. A specific magnetic transition from the weak ferromagnetic to the strong ferromagnetic state was discovered in the nanocrystalline SmCo(3) compound, which was considered to be related to the large anisotropic strain in the crystal lattice.