Magnetic Properties in the Pseudoternary SmFeMnC Alloys

The intrinsic magnetic properties of the tetragonal Sm₁₄ Fe_78-x,Mn_xC₈ , Ca sys tem are investigated. In addition to the sudden drop of σ_s, and T_c, an anomalous variation of the lattice constants is found. The sign of K₁ changes from negative to positive between x=15 and 20 at 1.5K, thus the cone-type anisotropy becomes uniaxial correspondingly. The intrinsic magnetic hardness effect at low temperature is observed at high Mn content.