Planar-type micro-electromagnetic actuators using patterned thin film permanent magnets and mesh type coils

Chao Zhi, Tadahiko Shinshi, Mikiko Saito, Kunio Kato

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

In this paper, we propose several types of planar micro-electromagnetic actuator that can be applied in micro-pumps and micro-valves. The various types each consist of a thin film permanent magnet (TFPM), a micro-coil and, in some cases, a ferromagnetic layer. The magnetic properties of a TFPM with a multilayered structure, comprising 300 nm thick NdFeB and 10 nm thick Ta layers deposited sequentially, are as high as bulk NdFeB magnets. Conventional micro-electromagnetic actuators consist of a bulk permanent magnet and a spiral micro-coil, whereas the actuators proposed in this paper consist of segmented patterns of TFPM, such as line/space and chessboard patterns, and mesh coils surrounding the segmented patterns. The TFPMs are segmented in order to reduce the demagnetization effect and to generate a large flux density. The proposed micro-coils possess a 2D structure and are easy to fabricate compared with spiral type micro-coils. The results of simulation show that the electromagnetic forces generated by actuators with segmented TFPMs are several times higher than one without segmentation. Furthermore, the actuation force performance is enhanced by covering the TFPM pattern with a ferromagnetic layer of Ni55Fe45 permalloy. The electromagnetic actuators are fabricated by a fully integrated MEMS process. The measured magnetic flux densities generated by the patterned TFPMs agree with the simulated results. The electromagnetic force between the patterned TFPM and the micro-coil is measured by an electronic force balance. Due to alignment errors between the micro-magnet and micro-coil, the experimentally measured forces are from 70% to 90% of the simulated ones.

Original languageEnglish
Pages (from-to)365-372
Number of pages8
JournalSensors and Actuators, A: Physical
Volume220
DOIs
Publication statusPublished - 2014 Dec 1

Fingerprint

permanent magnets
Permanent magnets
mesh
coils
Actuators
actuators
electromagnetism
Thin films
thin films
Magnets
magnets
flux density
Demagnetization
Magnetic flux
Permalloys (trademark)
demagnetization
MEMS
actuation
Magnetic properties
microelectromechanical systems

Keywords

  • Electromagnetic actuation
  • Ferromagnetic material
  • MEMS
  • Segmentation
  • Thin film permanent magnet

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials
  • Metals and Alloys
  • Surfaces, Coatings and Films
  • Instrumentation

Cite this

Planar-type micro-electromagnetic actuators using patterned thin film permanent magnets and mesh type coils. / Zhi, Chao; Shinshi, Tadahiko; Saito, Mikiko; Kato, Kunio.

In: Sensors and Actuators, A: Physical, Vol. 220, 01.12.2014, p. 365-372.

Research output: Contribution to journalArticle

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