Magnetic Aftereffect Constant of Nd-Fe-B Sintered Magnets

The magnetic field and temperature dependencies of the magnetic aftereffect constant Sv of Nd-Fe-B sintered magnets were studied for J-H demagnetizing curves between 293 and 400°K, the practical temperature range for permanent magnets. Sv is constant and independent of the magnetic field in the range from the point near (BH)max to the demagnetizing field whose magnetization J is -0.7 T. Sv decreased linearly as the temperature was increased. The value of Sv and the temperature dependence of Sv for Nd-Fe-B sintered magnets were both considerably larger than for Sm2Co17 sintered magnets.