Investigation of the magnetic properties of Dy doped Nd-Fe-B permanent magnet by using Mossbauer spectroscopy

摘要

The crystal and the magnetic properties of (Nd35.00-x Dy (x) )Fe bal.Cu0.15Co1.50Al0.20Nb0.35B1.00 (wt.%; x = 3.50, 6.00, and 8.00) samples are investigated by using x-ray diffractometer (XRD), vibrating smple magnetometer (VSM), and Mossbauer spectrometer. The crystal structure is determined to be tetragonal with the P4(2)/mnm space group. The saturation magnetization (M (s) ) decreases while the coercivity (H (c) ) increases with increasing Dy ion concentration. Based on the zero-filed-cooled (ZFC) curves, all the samples show spin reorientation, and the spin-reorientation temperature TSR decreases with increasing Dy ion concentration. The Mossbauer spectra measured at 295 K show decreasing < Hhf > with increasing Dy concentration, and the abrupt changes both in the magnetic hyperfine field (H (hf) ) and the electric quadrupole shift (E (Q)) at temperatures around T (SR) .