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Conception et réalisation de micro-capteurs à magnéto-impédance pour le contrôle non destructif

Abstract : The capability to detect micro-defects or buried flaws in the metallic parts is an important issue for the aerospace or nuclear industry. The technique of nondestructive testing (NDT) by eddy current is widely used for these applications. This thesis is part of collaboration project aimed at the realization and integration of magnetic field microsensors based on the magneto-impedance (MI) effect for the NDT detection systems. These multilayered structure microsensors (ferromagnetic/conductor/ferromagnetic) were realized in the clean room by thin film deposition method. A post-annealing step with magnetic field was then used to optimize the material properties and to induce magnetic anisotropy in the ferromagnetic layers. A method based on the double amplitude demodulation was proposed for the dynamic characterization of the sensors. The important parameters such as the geometry, the anisotropy and the driven frequency were studied in order to optimize the characteristics. The results showed that a bias field is necessary for the application. Therefore, we have investigated the possibility to realize, through thick micromoulding technique, a 3D microsolenoid and preliminary work on integrating a sensor in the microsolenoid by film transfer has been carried out. Finally, a theoretical study was investigated by taking into account the results obtained experimentally. For this purpose, the model of Landau-Lifshitz-Gilbert (LLG) has been implemented in an electromagnetic finite element calculation program in order to determine the impedance of the sensor as a function of the applied magnetic field.
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Submitted on : Saturday, March 7, 2015 - 1:00:59 AM
Last modification on : Tuesday, January 19, 2021 - 3:13:51 AM
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  • HAL Id : tel-01127227, version 1


Tao Peng. Conception et réalisation de micro-capteurs à magnéto-impédance pour le contrôle non destructif. Instrumentations et Détecteurs [physics.ins-det]. Université Paris Sud - Paris XI, 2014. Français. ⟨NNT : 2014PA112407⟩. ⟨tel-01127227⟩



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