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Heterostructures with magneto-electro-elastic coupling (e.g. multiferroics) are of paramount importance for developing new sensors, actuators and memories. With the progressive miniaturization of these systems it is necessary to take into account possible thermal effects, which may influence the normal operating regime. As a paradigmatic example we consider a recently introduced non-volatile memory element composed of a magnetostrictive nanoparticle embedded in a piezoelectric matrix. The distributions of the physical fields in this matrix/inclusion configuration are determined by means of the Eshelby theory, the magnetization dynamics is studied through the Landau–Lifshitz–Gilbert formalism, and the statistical mechanics is introduced with the Langevin and Fokker–Planck methodologies. As result of the combination of such techniques we determine the switching time between the states of the memory, the error probability and the energy dissipation of the writing process. They depend on the ratio kBT/v where T is the absolute temperature and v is the volume of the magnetoelastic particle. [ABSTRACT FROM AUTHOR]

Abstract: A fully integrated magnetic driven MEMS Micro-valve providing pulsed jets was developed and characterized for active aerodynamic control. The device is composed of a microvalve, a magnetostatic actuator and a packaging allowing accurate positioning on the models or prototypes. The microvalve is a resonator actuated by a specific coupling between an inductive driving coil and a NdFeB permanent magnet. The generated force was optimized to provide 250mN at 0.5A. High momentum rate, fully modulated pulsed jets have been obtained in the frequency range [0 – 500Hz] with velocities up to 150m/s. The actuation method allowed a good control over the pulsed jets characteristics that reached the required values for real scale automotive and aeronautic flow control experiments. [Copyright &y& Elsevier]

Abstract: We report the use of a magnetic instability of the spin reorientation transition type to enhance the magnetoelectric sensitivity in magnetostrictive–piezoelectric structures. We present the theoretical study of a clamped beam resonant actuator composed of a piezoelectric element on a passive substrate actuated by a magnetostrictive nanostructured layer. The experiments were made on a polished 150μm thick 18×3mm2 lead zirconate titanate (PZT) plate glued to a 50μm thick silicon plate and coated with a giant magnetostrictive nanostructured Nx(TbCo2 5nm/FeCo5nm) layer. A second set of experiments was done with magnetostrictive layer deposited on PZT plate. Finally, a film/film structure using magnetostrictive and aluminium nitride films on silicon substrate was realized, and showed ME amplitudes reaching 30VOe−1 cm−1. Results agree with analytical theory. [Copyright &y& Elsevier]

Hybrid giant magnetostrictive-piezoelectric film/film structures exhibiting magnetoelectric (ME) effect associated with a magnetic instability of the spin reorientation transition type are presented. We first present the theoretical study of a clamped beam actuator composed of a piezoelectric layer on a substrate actuated by a magnetostrictive layer. The actuator is a polished 50 μm thick 18×5 mm2 silicon substrate coated by an electrode, aluminum nitride, and magnetostrictive nanostructured layer. A ME coefficient of 30 V Oe-1 cm-1 at a 35 KHz longitudinal resonance was measured. Nonlinear excitation of this mode showed a “nonlinear” dynamic ME coefficient of 4 V Oe-1 cm-1. [ABSTRACT FROM AUTHOR]

We report the use of a magnetic instability of the spin reorientation transition type to enhance the magnetoelectric sensitivity in magnetostrictive-piezoelectric structures. We present the theoretical study of a clamped beam resonant actuator composed of a piezoelectric element on a nonpiezo substrate actuated by a magnetostrictive layer. The experiments are made on a polished 150 μm thick 18×3 mm2 lead zirconate titanate (PZT) plate glued to a 50 μm silicon plate and coated with a giant magnetostrictive nanostructured Nx(TbCo2 5nm/FeCo5 nm) layer. Another set of experiments was done with PZT substrate only. Results agree with analytical theory. [ABSTRACT FROM AUTHOR]