Commercial rare earth metals contain several atomic % oxygen, and intermetallics synthesized using these ingredients deviate markedly from the intended compositions. In this work, high purity rare earths (<20 ppm oxygen by weight) were used. Results for R2Fe14B systems with R = Y, Nd, Sm, or Gd have been previously reported. The earlier work has now been extended to include systems containing Ce, Pr, Dy and Er. All were ordered magnetically at room temperature, with Curie temperatures ranging from 437 K (Ce) to 592 K (Dy). Results suggest that Ce in this system exists in the quadripositive state. Saturation magnetizations (77 K) are 29.4, 34.8, 12.1, and 14.7 μB/formula unit, respectively, for R = Ce, Pr, Dy, and Er. These may be contrasted with 30.4 μB/f.u. for Y2Fe14B, which is the Fe magnetization alone. These results imply ferromagnetic coupling for Pr2Fe14B and antiferromagnetic coupling for the Dy and Er compounds. Room temperature anisotropy fields ranged from 37 kOe (R = Ce) to 158 kOe (R = Dy). Er2Fe14B exhibits a spin reorientation near room temperature. Pr2Fe14B, unlike Nd2Fe14B, exhibits no spin reorientation.

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Nd2-xPrxCo14B intermetallics crystallize in tetragonal form isostructural to Nd2Fe14B. Structural and magnetic properties of the polycrystalline materials have been determined. Room temperature magnetic measurements indicate that these intermetallics exhibit uniaxial anisotropy throughout the entire composition range. Substitution of praseodymium in Nd2-xPrxCo14B significantly enhances the anisotropy field both at 78 K and at room temperature. Magnetization versus temperature plots show spin reorientation TSR2 at 546 K for Nd2Co14B and at 668 K for Pr2Co14B. TSR2 increases linearly with composition x. The 3d sublattice anisotropy which seeks the tetragonal plane appears to dominate above these temperatures. In addition to the above, low temperature magnetic measurements demonstrate the spin reorientation in Nd2Co14B and Nd1.9Pr0.1Co14B. Further additions of praseodymium strengthen the axial anisotropy at temperatures down to 4.2 K. Effect of competing crystal field interactions and the consequences of praseodymium substitution that result in considerable increase in anisotropy field in these quaternaries are discussed.

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