Magnetic properties, domain structure, and microstructure of anisotropic SmCo6.5Zr0.5 ribbons with C addition

The magnetic properties and the domain structure of anisotropic melt-spun S mCo6.5Zr0.5 alloys with C addition was investigated by means of x-ray diffr action (XRD), magnetic measurement, and magnetic force microscopy. The XRD analyses showed that the addition of a few percent of C led to a significan t increase in the coercivity and simultaneously affected the characterizati on of crystalline texture of the ribbons. The easy magnetization c axis cha nged from parallel to the ribbon plane for SmCo6.5Zr0.5 ribbons to normal t o the ribbon plane for SmCo6.5Zr0.5C0.25-0.75 ribbons. An optimal coercivit y of 0.92 T was obtained for the SmCo6.5Zr0.5C0.5 ribbon spun at 5 m/s. The corresponding remanence measured normal or parallel to the ribbon plane wa s 7.1 kGs or 3.1 kGs, respectively. The domain structure was studied by mag netic force microscopey, A strip-shaped domain was observed on the surface of the SmCo6.5Zr0.5 ribbons and the walls lay straight and parallel. For C- doped ribbons, the domain walls formed a maze domain pattern of grains with c axis normal to the ribbon plane, Scanning electron micrographs showed th at a dendrite structure was present in the SmCoZr ribbon surface, and C add ition caused the above-mentioned dendrite to diminish.