Fouad Belhora

Enhanced magnetoelectric effect for flexible current sensor applications

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.

Magnetoelectricity in polyurethanes nanocomposites

ABSTRACT Magnetoelectric (ME) effect, triggered much interests because of its potential of the cross correlation between the electric and magnetic properties of matter for technical applications such as magnetic field sensors, transducers, actuators. Magnetoelectric (ME) effect represents the coupling between a change in electric polarization in a solid when a magnetic field is applied. This study reports on the magnetoelectric (ME) effect observed in nanocomposite polymer consisting of polyurethane (PU) filled with 2.5wt% and 5wt% of Fe3C magnetic nanoparticles. In general, the electric response to an applied magnetic field (H) on polymer composites filled by magnetic particles is not well known. That is the reason why our study aims to show the influence of the magnetic fillers (Fe3C) in PU matrix. Our experimental findings are discussed for different situations.

Mechanical energy harvesting using polyurethane/lead zirconate titanate composites

The microelectromechanical systems invade gradually the market with applications in many sectors of activity. Developing these micro-systems allows deploying wireless sensor networks that are useful to collect, process and transmit information from their environments without human intervention. In order to keep these micro-devices energetically autonomous without using batteries because they have a limited lifespan, an energy harvesting from ambient vibrations using electrostrictive polymers can be used. These polymers present best features against inorganic materials, as flexibility and low cost. The aims of this paper are manifold. First of all, we made elaboration of the polyurethane/lead zirconate titanate films of 100 µm thickness using a lead zirconate titanate–volume fraction of 50 %. Therefore, we did an observation of the lead zirconate titanate grains dispersion and the electrical characterization of the polyurethane–50 vol% lead zirconate titanate composites. Finally, a detailed study of the electromechanical transduction, for the polyurethane–50 vol% lead zirconate titanate unpolarized and polarized composites sustained to the sinusoidal mechanical strain with amplitude of 1.5% and at very low frequencies (f = 2 [Hz] and f = 4 [Hz]) and static electric field (Edc = 10 [V/µm]) or without it (Edc = 0 [V/µm]) has been presented.