Syntheses,crystalstructureandmagneticpropertiesofRm+nCo5m+3nB2n

<正> The phase relations at the 600℃and 700 ℃ isothermal sections of the ternary systems R-Co-B for R = Nd, Pr and R = Sm, Gd respectively were summarized in this paper. For Rm+nCo5m+3n B2n , two new types of compounds R3Co13B2(R = Pr, Nd, Sm, Gd, Dy, Ho, Er, Y) (m = 2, n =1) and R5Co19B6(R = Pr, Nd) (m = 2, n = 3) were synthesized by utilizing the principle of structural combination. Their crystal' structures and easy magnetization direction were determined by X-ray powder diffraction, and structures were refined by the Rietveld method. The Curie temperature Tc, saturation magnetization M, and anisotropic field HA of the new compounds were measured using a vibrating-sample magnetometer, an extraction sample magnetometer and M(H) - H curves of samples in different magnetization directions respectively. The Tc and Ms of Rm+nCo5m+3nB2n increase with increasing values of m at a given n value. HA increases with an increase in n when m is kept invariable. The effects of the substitution of Ni for Co on the magn