Elaboration de composites multiférroïque et caractérisation de l'effet magnétoélectrique

The magnetoelctric (ME) response consists in the modification of the electric polarization by an applied magnetic field (direct effect) or the modification of the magnetic polarization by an applied electric field (inverse effect). Intrinsic multiferroics are rather uncommon and the effect is often weak at room temperature. An alternative route to achieve ME effect, consists in using magnetostrictive and piezoelectric materials and coupling the two phases by mechanical stress. We draw (theoretically and experimentally) some material characteristics to achieve an importantME effect, which justify the use of ferrite and PZT. We describe the production process of the two studied connectivity schemes (stack of layers or inclusion of a phase in another). We focus on the sintering by Spark Plasma Sintering as a potential improvement of the mecanical bonding. We devoted a part of our work on multilayer composite and showed the importance of some factors such as the demagnetizing effect or the symmetry of the structure. We introduce a current sensor prototype suitable for electrical engineering application. We showed its good linearity and sensitivity but also some effects of its bandwidth.