Nucleation regions and coercivity determination of sintered Nd-Fe-B magnets

Yazid, MM; Olsen, SH; Atkinson, G

doi:10.1109/ICSAE.2016.7810214

Nucleation regions and coercivity determination of sintered Nd-Fe-B magnets

Lookup NU author(s): Muhsien Yazid, Dr Sarah Olsen, Dr Glynn Atkinson

Downloads

Full text for this publication is not currently held within this repository. Alternative links are provided below where available.

Abstract

© 2016 School of Mechanical and Systems Engineering. This paper describes the use of magnetic force microscopy MFM to observe magnetization reversal and nucleation in sintered permanent magnet materials. The investigated magnet is sintered Nd-Fe-B magnet. The domain structure is observed in both perpendicular and parallel surfaces to the alignment axis (easy axis) in a thermally demagnetized state. Maze-like and stripe-like magnetic domains are observed in perpendicular and parallel surfaces respectively. The nucleation regions are successfully observed at domain walls and presented in 3D with clear magnetic contrast images. The sample shows narrow magnetic domains with negative nucleation regions. The volume of nucleation site are determined and validated theoretically by developing an approach involving coercivity versus nucleus volume. It is shown that nucleation volume is proportional to coercive field. These insights can be useful for realizing Dy free Nd-Fe-B magnet with high coercivity.