Effect of the substitution of Gd for Sm on magnetic anisotropy of melt-spun Sm1-xGdxCo5 ribbons

Magnetically anisotropic Sm1-xGdxCo5 (0 less than or equal to x less than or equal to 0.5) ribbons have been prepared by single-roller melt spinning at a low wheel speed of 5 m s(-1) X-ray diffraction results show that the substitution of Gd for Sm enhances the relative intensity of the diffraction peak of index (200) and favours the formation of a strong (002) texture parallel to the longitudinal direction of the ribbons. This results in the increase of the remanence ratio with the increase of x. By scanning electron microscopy measurements, it is found that the Gd-containing ribbons have a more regular grain arrangement and a more homogeneous distribution of grain size compared to the Gd-free ribbons. The rectangularity of demagnetization curves is obviously improved with the increase of,v. A maximum remanence ratio (0.93) and best rectangularity of the demagnetization curves have been obtained for ribbons with x = 0.5. However, the replacement of Sm by Gd also leads to the linear decrease of the remanence of SmCo5 ribbons. The optimum magnetic properties, M-r = 0.84 T H-i(c) = 10.4 kOe, (BH)(max) = 16.7 MGOe, have been achieved in the as-annealed ribbons with x = 0.2.