Domain structures of die-upset melt-spun NdFeB

Domain patterns at the surface of thermally demagnetized MQIII, anisotropic Nd₂Fe₁₄B permanent magnet produced by hot pressing and die-pressing and die-upsetting melt-spun ribbons have been obtained by Kerr microscopy. Patterns have been observed on surfaces perpendicular, parallel, and at an angle of ∼25°, to the direction of easy magnetization. The magnetic domains are shown to have a mazelike structure on a scale of approximately 0.3-0.5 μm in the plane perpendicular to the c axis. In the plane parallel to the c axis a much finer magnetic structure was observed. There is evidence that domains extend across the interfaces between neighboring ribbons.