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 o r equal to 0.5) ribbons have been prepared by single-roller melt spinning a t a low wheel speed of 5 m s(-1) X-ray diffraction results show that the su bstitution of Gd for Sm enhances the relative intensity of the diffraction peak of index (200) and favours the formation of a strong (002) texture par allel to the longitudinal direction of the ribbons. This results in the inc rease of the remanence ratio with the increase of x. By scanning electron m icroscopy measurements, it is found that the Gd-containing ribbons have a m ore 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 r atio (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 al so leads to the linear decrease of the remanence of SmCo5 ribbons. The opti mum magnetic properties, M-r = 0.84 T H-i(c) = 10.4 kOe, (BH)(max) = 16.7 M GOe, have been achieved in the as-annealed ribbons with x = 0.2.