Effect of Fe, Cu, Zr, and Ti on the magnetic properties of SmCo-1:7 magnets

The effect of Fe, Cu, Zr, and Ti substitution on magnetic properties of SmCo 1:7 magnets at temperatures up to 500/spl deg/C were studied. As-milled amorphous Sm(Co,Fe,Cu,Ti-Zr)/sub 7/ magnets crystallized in the TbCu/sub 7/-type structure after annealing at 750/spl deg/C for 2 h. A room-temperature intrinsic coercivity of around 2.5 T is obtained for compositions SmCo/sub 6.4/ Zr/sub 0.2/Ti/sub 0.4/ and SmCo/sub 6.4/Fe/sub 0.1/Zr/sub 0.1/Ti/sub 0.4/. The high coercivity of the ball-milled SmCo/sub 7-x/Ti/sub x/ magnets is attributed to the strong pinning of the walls of the "interaction domains" by the network of grain boundaries between the nanocrystalline grains. The virgin curve of the ball-milled samples is suggestive of strong domain wall pinning.