Temperature dependence of magnetic hysteresis in melt-spun and sintered Nd-Fe-B magnets

The hard magnetic properties of melt-spun and sintered Nd-Fe-B with small substitutions of Al and Dy have been investigated in the temperature range of 4.2-600 K. High temperature magnetic measurements do not show any clear evidence of a secondary pinning phase with a curie temperature at around 150°C. Low temperature measurements show a shoulder in the demagnetization curve below the spin reorientation temperature which is largest for the isotropic melt-spun samples.