Magnetic flux loss in Nd–Fe–B magnet irradiated with 660 MeV carbon ion beam

Irradiations effect on the magnetic flux of Nd2Fe14B magnets have been investigated using 660 MeV C6+ and 200 MeV protons over a dose range from 24 Gy to 105 Gy. For both cases, the flux loss as a function of the absorbed dose are nearly the same values over a wide dose region from 50 Gy to 30 kGy. An absorbed dose of 1.3–1.4 kGy results in a flux loss of about 50%. Re-magnetization of the irradiated magnets recovers the magnetic flux to the original level similar as thermal heating.