Papers by Keyword: Coercivity Mechanism

Abstract: Using the electron microscopy (SEM and TEM), X-ray structure analysis and precise magnetometry methods (VSM, SQUID-magnetometer), the microstructure and magnetic hysteresis properties of industrial manufactured hard magnetic rare-earth based alloys of Nd-Fe-Co-B compositions (BZMP and MQP-B brands) that are widely applied as fillers for bonded magnets (magnetoplasts and magnetoelasts) have been studied. The obtained results allow selecting the proper temperature range for bonded magnets applications on the base of BZMP and MQP-B fillers.

Abstract: It is discussed the difference between the magnetic reversal mechanisms: i) coherent rotation, ii) nucleation, iii) unpinning of domain walls. The main argument to suggest pinning as the coercivity mechanism of Sm(CoFeCuZr)z magnets is the low initial susceptibility of magnetization curves of thermally demagnetized magnets. However, coherent rotation also implies in low initial susceptibility, since the grain size of the magnets is near the single domain particle size. It is unlikely that pinning could be the coercivity mechanism in this case, since the anisotropy field of Sm2Co17 phase is 65 kOe, whereas the coercivity of magnets can be higher than 40 kOe. Such coercive field of 60% of the anisotropy field indicates coherent rotation as mechanism. A model for describing the abnormal coercivity behavior in Sm(CoFeCuZr)z magnets is proposed.

Abstract: It is discussed the difference between the magnetic reversal mechanisms: i) coherent rotation, ii) nucleation, iii) unpinning of domain walls. The main argument to suggest pinning as the coercivity mechanism of Sm(CoFeCuZr)z magnets is the low initial susceptibility of magnetization curves of thermally demagnetized magnets. However, coherent rotation also implies in low initial susceptibility, since the grain size of the magnets is near the single domain particle size. It is unlikely that pinning could be the coercivity mechanism in this case, since the anisotropy field of Sm2Co17 phase is 65 kOe, whereas the coercivity of magnets can be higher than 40 kOe. Such coercive field of 60% of the anisotropy field indicates coherent rotation as mechanism. A model for describing the abnormal coercivity behavior in Sm(CoFeCuZr)z magnets is proposed.