Structure and magnetic properties of Sm(CobalFexZr0.05Cu0.08GayBz)12 alloys

3d-rich alloys and their melt-spun materials with nominal compositions of Sm(Co_balFe_xZr_0.05Cu_0.08Ga_yB_z)₁₂ (x=0.1-0.41, y=0-0.01, z=0.01-0.02) were synthesized and characterized in the temperature range of 10-1473 K and at fields up to 5 T. The main phase of the as-cast alloys was formed in a Th₂Ni₁₇ type structure, exhibiting a strong uniaxial anisotropy. As a result, encouraging hard magnetic properties with T_c=995-1086 K, H_a=40-115 kOe, M_s=10-12.8 kG at 300 K, and H_a=60-180 kOe, M_s=10.4-13.6 kG at 10 K were observed in the as-cast alloys. The melt-spun materials are nano-structured in nature and magnetically hard, even in the as-spun state. The following hard magnetic properties were observed: H_ci=7-10 kOe, 4πM_s=9.4-11.7 kG, at 300 K, and H_ci=17-27 kOe, 4πM_s=9.6-12.1 kG, at 10 K. The highest (BH)_max∼9.8 MGOe at 300 K was obtained from the Sm(Co_balFe_0.31Zr_0.05Cu_0.08B_0.02)₁₂ ribbon material. A Henkel plot analysis indicates the existence of a strong exchange-coupling interaction between the magnetically hard and soft phases in these ribbon materials. The effects of adding Ga, B, and Fe on the magnetic properties will be discussed.