Magnetic Parameters of R_2Fe_(14)B Compounds with Nanograin Structure

摘要

High-purity compounds R_2Fe_(14)B (R = Y, Gd, Tb, Dy, Ho and Er) were prepared by arc melting using rare-earth metals purified by vacuum distillation-sublimation. The compounds R_2Fe_(14)B are single-phase and have well-defined directional structure. Nanocrystalline structure was formed by severe plastic deformation of the samples by means of torsion for 5 turns on the Bridgeman anvil under the pressure of 4 GPa at room temperature. The performed investigations of magnetic properties of these compounds allowed us to obtain reliable quantitative data on the intrinsic magnetic parameters, such as saturation magnetization, Curie temperature, the remanent magnetization and coercive force. The enhancement of the remanent magnetization was observed for R_2Fe_(14)B in nanocrystalline states compared with the crystalline samples due to the intercrystalline exchange interactions.