Magnetic aftereffect of Nd-Fe-B sintered magnets

The magnetic field and temperature dependences of the magnetic aftereffect constant S_v were measured for Nd-Fe-B sintered magnets in the temperature range between 200 and 500 K on a J-H demagnetizing curve. It was found that S _v is constant and independent of the magnetic field in the range from H_m to H_cJ. S _v decreases linearly between 200 and 500 K as the temperature increases and is larger in materials whose H_cJ is large. The temperature dependence of S_v for Nd-Dy-Fe-B and Nd-Fe-Co-B sintered magnets differs from that in SmCo₅ magnets and is similar to that in Sm₂Co₁₇ sintered magnet. However, the value of S_v for Nd-Fe-Co-B sintered magnet is larger than that of Sm₂Co₁₇ magnets by roughly 2.5 to 3 times