Magnetic properties of Nd2Fe14-xBexB

Be-substituted Nd₂(Fe_14-xBe_x)B compounds have been successfully prepared. The observed linear reduction of unit cell volume with Be substitution indicates that the Be atoms enter almost exclusively the Fe sites. Both the Curie temperature and magnetization are weakened upon Be substitution; the reduction in T_c is about 26 K/Be atom and the reduction in the average Fe moment is about 0.26 μ_B/Be atom, respectively. The fits to room temperature Mossbauer spectra of Nd₂(Fe₁₃Be)B give an average hyperfine field of 23.7 T. The room temperature anisotropy of Be substituted Nd₂(Fe_14-xBe_x )B compounds is around 8 T which is nearly unchanged, compared to the parent Nd₂Fe₁₄B compound. Moreover, the Be substitution leads to an increase in the canting angle at 10 K, from 28° to ~36°, and a decrease in the spin-reorientation temperature from 131 K to 123 K for Be_0.5 and 112 K for Be _1.0 substitution, respectively. These effects indicate a weakened A₂₀ value and/or an enhanced A₄₀ value for Nd atoms