Temperature stable rare earth magnetic powder Sm-Fe-N based micro magnets with remanence enhanced by easy axis alignment and its application in MEMS actuator

Huayu Wang, Masashi Matsuura, Shusuke Yamada, Satoshi Sugimoto, Shuji Tanaka

Research output: Contribution to journalArticlepeer-review

Abstract

In this paper, we report an actuator with a magnet made of novel rare earth magnetic powder Sm-Fe-N with diameter of 2 µm to 5 µm. Micro magnets were fabricated by mixing the magnetic powder with wax at temperature of 90 C. Alignment of the easy axis process was employed to enhance the remanence of the micro magnets. A 8 T strong pulse magnetic field was utilized to magnetize the micro magnets. The properties of magnetic powder were revealed with vibrating sample magnetometer by measuring micro magnets with various magnetic powder weight loading percentages. In the best condition, the remanence reaches 0.9 T and the energy product reaches 70 kJ m-3. After that, the electromagnetic actuator was fabricated by embedding the magnetic powder in deep-reactive-ion-etched Si cavity with wax binder and parylene capping. The completed microelectromechanical system structure was mounted on a four-layer printed circuit board with embedded coils. Upon the application of a direct current for actuation, a displacement of 180 μm was obtained from a device volume of only 1.5 mm3 with a low actuation power consumption of 11.5 mW.

Original languageEnglish
Article number075002
JournalJournal of Micromechanics and Microengineering
Volume31
Issue number7
DOIs
Publication statusPublished - 2021 Jul

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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