Proceedings of the
9th International Conference of Asian Society for Precision Engineering and Nanotechnology (ASPEN2022)
15 – 18 November 2022, Singapore

Fine Magnetic Pattern Transferred on Nd-Fe-B Magnets UsingHigh Heat-resistant Nd-Fe-B Magnets

Keita Nagai1, Naohiro Sugita2, and Tadahiko Shinshi2,a

1Department of Mechanical Engineering, Tokyo Institute of Technology, R2-38, 4259 Nagatsuta-Cho, Midori-Ku, Yokohama, 226-8503, Japan

2Institute of Innovative Research, Tokyo Institute of Technology, R2-38, 4259 Nagatsuta-Cho, Midori-Ku, Yokohama, 226-8503, Japan


High-performance electromagnetic MEMS devices are desired in IoT development. Fine-pitch and multi-pole magnetization are necessary to reduce the demagnetization field in the magnet and increase the surface magnetic flux density. Efficient magnetic circuits can be realized by forming various micro magnetic patterns. Laser-assisted heating magnetization has been developed for the fine-pitch and multi-pole micro magnetization of Nd-Fe-B magnets. However, it has the disadvantage of long patterning time due to laser scanning along with the desired magnetic pattern, making it unsuitable for mass production. This study aims to develop a batch transfer method for micro magnetic patterns of electromagnetic MEMS devices. The micromagnetic patterns are generated by laser-assisted heating on a master Nd-Fe-B magnet having high heat resistance. The magnetic pattern is transferred to the target Nd-Fe-B magnets by utilizing the difference in coercive forces between the master and target magnets when the temperature rises. The master Nd-Fe-B magnet can be used multiple times due to its high heat resistance. We have successfully transferred the line type alternating poles of 16 with a pitch of 0.3 mm to a target Nd-FeB magnet (5×5×t0.5 mm, Br: 1.19 T, Hcb: 868 kA/m) at a temperature of 160 °C. A thin plate Nd-Fe-B magnet having a high heat resistance (5×5×t0.3 mm, Br: 1.29 T, Hcb: 907 kA/m, Work. Temp.: 200°C) was used as a master magnet. The measured surface flux density on the target magnet is 137 mT in amplitude, which is 54.4 % of the ideal value.

Keywords: Magnetic pattern transfer, Fine pitch magnetization, Multi-pole magnetization, Magnetic MEMS, Laser-assisted heating

PDF Download