Magnetic Domain Structure: Analysis of Magnetic Reversal in RE-3d Permanent Magnets

The possibilities of direct magnetic domain observation on surfaces of modern permanent magnets SmCo5, Sm-Zr-Co-Cu-Fe, Nd-Fe-B by means of the magneto-optical Kerr effect for the quantitative and qualitative testing of magnetization and magnetic reversal processes and nature of magnetic hysteresis were analyzed. For all types of investigated magnets, the angular dependences for saturation field HS, critical field of reverse domain removal HK, and nucleation field Hn of individual grains were found to obey the law 1/cosϕ, where ϕ is the angle between the grain easy axis and external magnetic field.