To obtain the accurate magnetic properties of Nd-Fe-B sintered magnets with high coercivity (H_(cJ)), the author examined the use of a pulsed-field magnetometer (PF) and a hysteresis graph (HG) method using an extra large-sized electromagnet. To prevent the effects of machining on magnetic properties, the samples were selected for a diameter of 10 mm and the length (L) of 7-21 mm. Reliable calibrations and corrections of the magnetization and the magnetic field were very important, especially for the longer L to magnetize uniformly for both the methods. To correct the demagnetizing field and obtain exact differential susceptibility near H_(cJ), L had to be more than 14 mm for the PF method. The correction of magnetization distortion using AlNiCo of L = 21 mm was suitable for the HG method.
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