New magnetic material based on SmCo4B

Abstract

The compound SmCo4B is a hard magnetic material; however, the saturation moment and the Curie temperature need to be increased for the compound to be a candidate for a permanent magnetic material. For this purpose, Fe substitution for the Co and Pr substitution for the Sm of SmCo4B have been attempted. In addition, the nitrogenation of SmCo2Fe 2 is also attempted. The magnetic characteristics of SmCo 2Fe2B have been investigated in a pulsed high magnetic field up to 350 kOe, and the data are compared with those of other related compounds investigated in this work. The compound with more Fe content, SmCo1.7Fe2.3B, has been successfully made, and T C=794 K and saturation moment Ms=81.4 emu/g at 300 K have been obtained. It is found that the Fe substitution does not decrease the uniaxial magnetic anisotropy. Heat treatments in nitrogen gas at 500°C of SmCo2Fe2B have brought about significant increases of magnetization; however, the increase of TC is only about 20 K and the crystal volume is unchanged to within experimental uncertainty.