Nanogranular, Melt-Spun Intermetallic Compound SmNi: Magnetocaloric Effect and Large Coercivity

Rare earth intermetallic compound SmNi has been synthesized by melt spinning under argon atmosphere. This sample crystallizes in orthorhombic structure (CrB-type, Space group Cmcm, No. 63) and exhibits texture and nanograin formation. The average crystallite size calculated from powder X-ray diffraction data is ~17 nm. Melt-spun SmNi orders ferromagnetically at ~47 K (T
_C
) and this is close to T
_C
of the arc-melted sample. The saturation magnetization value at 10 K is only ~24 μ
_B
/f.u., whereas a large coercivity of ~24 kOe is observed. Isothermal magnetic entropy change, ASm, shows a maximum at T
_C
, of ~-1 J/kg · K, for 50 kOe field change with a relative cooling power value of ~10 J/kg. Small moment of Sm, strong magnetocrystalline anisotropy, complex magnetic structure, and nanograin size all influence the magnetism of melt-spun SmNi.