Effect of the M/Co substitution on magnetocrystalline anisotropy and magnetization in SmCo5-xMx compounds (M=Ga;Al)

The isothermal magnetization curves were carried out on magnetically aligned powder of the SmCo4Ga and SmCo4Al samples; they have been measured at 4.2 K in applied field up to 33 T produced by a water-cooled resistive magnet. The intrinsic magnetic properties such as saturation magnetization, anisotropy constant, and anisotropy field have been derived. Whereas some properties, such as the saturation magnetization or the Curie temperature are found to be strongly reduced upon Ga or Al for Co substitution, on the contrary the magnetocrystalline anisotropy is much larger for the substituted compounds. Hysteresis cycles are presented also and coercivity ranging from 4.5 to 6 T are reported. The mechanism at the origin of the coercivity is also modified from a nucleation type for SmCo5 to a pinning type for the Ga or Al containing compounds. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3339776]