Radiation damage in Nd-Fe-B magnets : temperature and shape effects

Nd2Fe14B permanent magnets with different load lines were irradiated with 20 MeV protons at temperatures between 300 and 15 K, and the flux loss was measured as a function of the irradiation temperature. The results show that the magnetic flux loss depends drastically on temperature and on the shape of the sample. A new theoretical model which explains the observed temperature dependence of irradiation effects is introduced.