This article focuses on the magnetoelectric (ME) effect that could be obtained in a bilayered structure consisting of the Cytop polymer and a magnetic tape filled with magnetically soft particles. The ME behavior was characterized by measuring the amplitude of the magnetoelectric current versus various input parameters that appear in theoretical expressions, i.e., the bias magnetic field, the alternative magnetic field, and the applied frequency. Experimental results were investigated together with theoretical models in order to determine the ME coupling value. It was found that the laminate material of a transversely charging electret along with bias magnetic tape could attain significant magnetoelectric properties, which were the result of the mechanical contacts between the layers and the electric-mechanical and magnetic-mechanical coupling in each phase. All the results demonstrated a possibility to realize a low-cost flexible current sensor while achieving an improved magnetoelectric response.

Interest in energy harvesting applications has increased a lot during recent years. This is especially true for systems using electroactive materials like dielectric polymers or piezoelectric materials. Unfortunately, these materials despite multiple advantages, present some important drawbacks. For example, many dielectric polymers demonstrated high energy densities; they are cheap, easy to process and can be easily integrated in many different structures. But at the same time, dielectric polymer generators require an external energy supply which could greatly compromise their autonomy. Piezoelectric systems, on the other hand, are completely autonomous and can be easily miniaturized. However, most common piezoelectric materials present a high rigidity and are brittle by nature and therefore their integration could be difficult. This paper investigates the possibility of using hybrid systems combining piezoelectric elements and dielectric polymers for mechanical energy harvesting applications and it is focused mainly on the problem of electrical energy transfer. Our objective is to show that such systems can be interesting and that it is possible to benefit from the advantages of both materials. For this, different configurations were considered and the problem of their optimization was addressed. The experimental work enabled us to prove the concept and identify the main practical limitations.

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Electroactive polymers (EAP) are relatively soft and flexible materials, easy to integrate and able to undergo large deformations by applying an electric field (usually some 10 V/μm). This coupling between strain and electric field (quadratic by nature) as well as particular mechanical properties have already been used advantageously to design actuators. As energy harvesters, EAP have also shown good abilities by providing energy densities up to 0.4 J/g/cycle (generator integrated in a shoe). Moreover, they present some advantages over other techniques as electromagnetic or piezoelectric as they have low resonance frequency response and high elasticity which enable them to be used in situations where large displacements are available. The main drawback of EAP as energy harvesters is that they don't experience direct coupling between strain and electric field, such as the piezoelectric effect. It is therefore essential to use an external electrical polarization source in order to create energy cycles induced by the EAP capacitance variations when it is subject to external stress. The goal of this work is to combine the EAP and piezoelectric materials using the advantages of both, for a hybrid energy harvesting. Different possible configurations and their performances are studied and a comparison with existing techniques is made.