Browsing by Author "Fang, Lin-Huei"

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Self-Magnetization-Switchable Micro-Magnetic Track Based Magnetic-Bead Manipulation
(2018-01-01)
Chung, Tien-Kan
;
Fang, Lin-Huei
;
Liu, Tzu-Wei
;
Chu, Hou-Jen
;
Ranabotu, Jaganmohan Reddy
In this paper, we report a self-magnetizationswitchable magnetic-track based magnetic-bead manipulation on a silicon wafer. The manipulation approach consists of a thermomagnetic NiCu micro-disc track (which is deposited on the silicon wafer), micro magnetic bead, a thermoelectric generator (TEG; which is placed beneath the silicon wafer), and four external electromagnets (which are used to produce a directional magnetic field). The Curie temperature of the NiCu micro-disc track is approximate room temperature. Due to this, when the TEG cools the NiCu micro-disc track lower than its Curie temperature (i.e., lower than room temperature), the track becomes ferromagnetic. However, when the TEG heats the NiCu micro-disc track higher than its Curie temperature (i.e., about or higher than room temperature), the track becomes paramagnetic. Therefore, by alternative cooling and heating, the track is switched between ferromagnetic and paramagnetic (i.e., magnetic moment is changed between normal and very small). This achieves on-chip self-magnetization-switchable track. Furthermore, when a directional magnetic field is applied to the track which becomes ferromagnetic, the track can guide the bead manipulation. Alternatively, when the track becomes paramagnetic, the track cannot guide the bead manipulation. This novel selfmagnetization-switchable magnetic-track-guided bead manipulation provides an important alternative bead manipulation for biomedical NIEMS/NEMS systems.
THERMOMAGNETIC MICRO-TRACKS-GUIDED MAGNETIC BEAD MANIPULATION: A DEMONSTRATION OF MOVING BEAD ACROSS DIFFERENT TRACKS ENABLED BY NOVEL EMBEDDED ON-CHIP MICRO HEATING WIRES
(2019-01-01)
Fang, Lin-Huei
;
Duan, Hao
;
Chen, Chin-Chung
;
Cheng, Chin-Cheng
;
Chung, Tien-Kan
In this paper, we show a demonstration of moving bead across different tracks enabled by novel embedded on-chip micro heating wires for thermomagnetic micro-tracks-guided magnetic bead manipulation. The demonstration includes a magnetic-bead-manipulation chip (which consists of thermomagnetic NiCu micro-disk tracks deposited on top of on-chip platinum micro heating wires fabricated on top of a silicon substrate), a magnetic bead, a thermoelectric generator (TEG), a pulse-generation circuit, and four external electromagnets. Because curie temperature of the track is approximate in room-temperature range, when we apply a pulse current to the heating wires to individually heat the track higher than room temperature, the magnetic property of the track is switched to paramagnetic. Oppositely, when we apply a current to TEG to cool the track lower than room temperature, the track is switched to ferromagnetic. By sequentially/selectively heating or cooling the tracks to switch the tracks to paramagnetic or ferromagnetic, together with applying directional magnetic field, we can achieve moving bead across different NiCu micro-disk tracks. This is an important and significant progress for conventional thermomagnetic micro-tracks-guided magnetic bead manipulation which cannot demonstrate moving bead across different tracks. Therefore, our approach provides a new and complete thermomagnetic micro-tracks-guided magnetic bead manipulation for lab-on-chip micro systems and biomedical MEMS/NEMS.