Novel coil-less room-temperature resettable magnetic-bead manipulation by using thermomagnetic tracks

Tien Kan Chung*, Chih Cheng Cheng, Jaganmohan Reddy, Jeng Han Chiou

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


In this paper, we report a novel coil-less room-temperature resettable magnetic bead manipulation by using thermomagnetic Gd tracks. When comparing to conventional magnetic-track-guided magnetic bead motion, the thermomagnetic Gd tracks (whose Curie temperature is at room temperature) not only can guide the bead motion (as well as the conventional tracks) but also can be reset (demagnetized) in room temperature range without use of any conventional reset coil (i.e., superior than the conventional tracks). The operation and reset principles are described below. When a Gd track is cooled (by a thermoelectric generator, TEG) lower than its Curie temperature (for example: 5 °C), the Gd track becomes ferromagnetic. Furthermore, under a magnetic field, the ferromagnetic Gd track enables the magnetic-track-guided magnetic-bead manipulation. Oppositely, when the Gd track is heated (by the TEG) higher than its Curie temperature (for example: 50 °C), the Gd track becomes paramagnetic. Thus, under the magnetic field, the paramagnetic Gd track cannot attract the bead. This achieves the track resetting/demagnetizing through a coil-less room-temperature approach and thus disables the magnetic-track-guided magnetic bead manipulation. Furthermore, according to above principles, we can sequentially use TEGs to cool and heat different Gd tracks to guide the bead moving across different tracks, and also reset/demagnetize any track anytime during the bead motion through our approach. These results would be important fundamental elements to provide an alternative magnetic-bead-manipulation for biomedical MEMS systems.

Original languageEnglish
Article number111856
Number of pages16
JournalSensors and Actuators, A: Physical
StatePublished - 1 Apr 2020


  • Actuation
  • Bead manipulation
  • Bead motion
  • Coil-less
  • Demagnetize
  • Magnetic
  • Resettable
  • Thermomagnetic
  • Track guided

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