Magnetic properties of Nd2(Fe1-xCox)14B and Y2(Fe1-xCOx)14B

Magnetic properties of Nd2(Fe1-xCox)14B and Y2(Fe1-xCox)14B have been studied by magnetic measurements and x-ray diffraction. Magnetocrystalline anisotropy of Y2(Fe1-xCox)14B decreases monotonically with increasing Co concentration at room temperature, but increases and reaches a maximum at about x=0.4 and 0.2 for T= 1.5 K and 150 K respectively. The effect of substituting Co for Fe on spin reorientation temperature is complicated for the Nd2(Fe1-xCox)14B. Saturation magnetization has a maximum value at about x=0,1 at 1.5 K. Curie temperature is enhanced significantly by the substitution of Co for Fe. The effects of Co on Curie temperature are almost the same for both Nd2(Fe1-xCox)14B and Y2(Fe1-xCox)14B, indicating that Curie temperature is essentially determined by the 3d-3d atom exchange interactions.