Capteurs à ondes élastiques de surface (SAW) pour champs magnétiques à base de structures multicouches piézo-magnétiques

Abstract : The aim of this Ph.D. Thesis is to study piezo-magnetic surface acoustic wave (SAW) sensor. Accurate and fully coupled physical model was numerically implemented in order to investigate the sensitivity of SAW devices using the magneto-elastic interaction with an external magnetic field. The different parameters of the structure, including the thicknesses of the various layers and their natures were theoretically optimized with regard to the quality factor, the electromechanical coupling factor and the sensitivity to the magnetic field. Devices using the optimal settings have been made and characterized, and their performance compared to the theoretical prediction. We have shown that the sensor can be designed to meet the needs of the application as regards the range of the field strength to be measured and the target sensitivity. Thus the CoFeB used as magneto-elastic sensitive layer provides better sensitivity but on a narrow stretch of the magnetic field while the nickel expands the measurement range but with less sensitivity. We have also shown that the use of hard material as insulating layer, such as alumina, allows better sensitivity. This sensitivity is also greatly increased when the sensor is operating at high frequencies
Document type :
Theses
File URL :
http://docnum.univ-lorraine.fr/prive/DDOC_T_2015_0321_ELHOSNI.pdf
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https://hal.univ-lorraine.fr/tel-01754628
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Submitted on : Friday, March 30, 2018 - 9:55:29 AM
Last modification on : Tuesday, August 21, 2018 - 9:46:04 AM

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  • HAL Id : tel-01754628, version 1

Citation

Meriem Elhosni. Capteurs à ondes élastiques de surface (SAW) pour champs magnétiques à base de structures multicouches piézo-magnétiques. Autre [cond-mat.other]. Université de Lorraine, 2015. Français. ⟨NNT : 2015LORR0321⟩. ⟨tel-01754628⟩

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