Browsing by Author "Chen, I-Lun"

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A Novel MEMS DC Magnetic Sensor Using Thermomagnetic-Piezoelectric Materials with a Coil-Less Reset Approach
(2018-01-01)
Chen, Chin-Chung
;
Chen, I-Lun
;
Duan, Hao
;
Chung, Tien-Kan
;
機械工程學系
We report a novel MEMS DC magnetic sensor using thermomagnetic-piezoelectric materials with a coil-less magnetization-reset approach. The magnetic sensor consists of a silicon MEMS diaphragm, a piezoelectric PZT thin film, and a thermomagnetic Gadolinium (Gd) sheet. Due to the Gd's thermomagnetic property, the sensor at low temperature (for instant, 9 degrees C.; below its Curie temperature which is in room temperature range) can sense ambient DC magnetic fields. Without using on-chip coils, the sensor can be easily reset by heating the sensor higher than its Curie temperature (for example, 45 degrees C. According to experimental results, the sensor successfully senses DC magnetic field from 2 to 100 Gauss and is 45 degrees C. When comparing to conventional NEMS, MEMS, and AMR magnetic sensors (i.e., using magnetic materials requiring on-chip magnetization-reset coils which occupy huge chip footprint), our sensor with the coil-less reset approach can significantly reduce the sensor footprint.
A thermomagnetic-piezoelectric MEMS AC magnetic-field sensor demonstrating a novel room-temperature-range coil-less resetting/demagnetizing approach
(2019-10-01)
Chen, Chin-Chung
;
Chen, I-Lun
;
Duan, Hao
;
Tseng, Chia-Yung
;
Chung, Tien-Kan
We report a novel thermomagnetic-piezoelectric MEMS AC magnetic-field sensor. The magnetic sensor consists of a silicon MEMS diaphragm, a piezoelectric PZT thin film, and a thermomagnetic Gadolinium (Gd) film covered by a Pt anti-oxidation layer. Due to the thermomagnetic-Gd/piezoelectric-PZT layered structure, the sensor not only can sense AC magnetic field, but also can be reset/demagnetized automatically at temperature higher than Gd's Curie temperature which is in room-temperature range. Experimental results show that the sensor successfully senses AC magnetic field from 1 to 14 Gauss at 9 degrees C, and is automatically reset/demagnetized at 45 degrees C. While conventional MEMS and AMR magnetic sensors using magnetic materials require on-chip resetting/demagnetizing coils which need a huge footprint of the chip, our sensor utilizing the coil-less resetting/demagnetizing approach significantly reduces the sensor footprint. In the other hand, when comparing to conventional coil-less resetting/demagnetizing method (i.e., annealing magnetic material at hundreds degrees C), our coil-less resetting/demagnetizing approach is at room-temperature range (for instant, 45 degrees C). (C) 2019 Elsevier B.V. All rights reserved.