Spin-MEMS microphone integrating a series of magnetic tunnel junctions on a rectangular diaphragm
| Autor: | Yoshihiko Fuji, Tomohiko Nagata, Michiko Hara, Akiko Yuzawa, Tomio Ono, Kei Masunishi, Kazuaki Okamoto, Shotaro Baba, Yoshihiro Higashi, Shiori Kaji |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
010302 applied physics
Microelectromechanical systems Materials science Series (mathematics) Spintronics Microphone Acoustics General Physics and Astronomy Diaphragm (mechanical device) 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Computer Science::Other Condensed Matter::Materials Science Magnetization Tunnel magnetoresistance 0103 physical sciences 0210 nano-technology Spin (aerodynamics) |
| Zdroj: | Journal of Applied Physics. 123:163901 |
| ISSN: | 1089-7550 0021-8979 |
| DOI: | 10.1063/1.5023756 |
| Popis: | We investigate the enhancement of the signal-to-noise ratio (SNR) of spintronic micro-electro mechanical-system (Spin-MEMS) microphones in which spintronic strain-gauge sensors (Spin-SGSs) are integrated on a micro-electro mechanical-system (MEMS) diaphragm by using a large array of N Spin-SGSs connected in series similar to that in a previous report on magnetic tunnel junction magnetic sensors. Since the strain-gauge properties of Spin-SGSs strongly depend on the angle between the applied uniaxial strain and the magnetization direction of the reference layer, in order to obtain the same signals from each Spin-SGS in an array, it is necessary to locate the Spin-SGS array in a region where the uniaxial strain occurs uniformly on the MEMS diaphragm. We theoretically and experimentally investigate the effect of the diaphragm shape on uniaxial strain on the diaphragm surface. As a result, it is found that a rectangular-shaped diaphragm provides a larger region in which a uniform uniaxial strain is applied to the Spin-SGS array compared with the generic circular diaphragm. Finally, an SNR enhancement of 18 dB by connecting N = 62 Spin-SGSs in series is successfully confirmed in a Spin-MEMS microphone with a rectangular diaphragm. |
| Databáze: | OpenAIRE |
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