Publications by authors named "Johan Moulin"

MEMS actuators rely on the deformation of silicon structures. Using dimensions smaller than dozens of micrometers reveals that the micro-electro-mechanical systems (MEMS) actuators are affected by fabrication inaccuracies, leading to hardly predictable forces and/or actuation results. In this paper, MEMS bistable buckled beam actuators are presented.

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This paper reports the development of a methodology combining microstrip ferromagnetic resonance and digital image correlation in order to simultaneously measure the voltage-induced strains and the magnetic resonance in artificial magnetoelectric heterostructures ("magnetic films/piezoelectric substrate" or "magnetic films/flexible substrate/piezoelectric actuator"). The overall principle of the technique and the related analytical modelling are described. It is powerful to estimate the magnetostriction coefficient of ferromagnetic thin films and can be used to determine the effective magnetoelectric coefficient of the whole heterostructures in addition to the piezoelectric coefficient related to the in-plane voltage-induced strains.

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A detailed understanding of the formation of magnetic vortices in closely spaced ferromagnetic nanoparticles is important for the design of ultra-high-density magnetic devices. Here, we use electron holography and micromagnetic simulations to characterize three-dimensional magnetic vortices in chains of FeNi nanoparticles. We show that the diameters of the vortex cores depend sensitively on their orientation with respect to the chain axis and that vortex formation can be controlled by the presence of smaller particles in the chains.

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