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The stability under dynamic mechanical solicitation and with the temperature of the elastomagnetic composite made of Sm2Co7 particles embedded in a silicone matrix is investigated. The thermal stability was examined by DSC measurements. The thermal (up to congruent to 340 degrees C) and mechanical ageing effects on the material elastomagnetic response were investigated by measuring the amplitude, V-0, of the electromotive force induced in a pick-up coil during the dynamic mechanical solicitation of the sample. It was found that for the whole investigation range of temperatures, the V, dependence on the frequency, v, and amplitude, D, of the externally induced deformation is linear and its amplitude is not changing for treatments up to 150 degrees C; for higher temperature treatments the response amplitude is decreasing. The analysis of the response signal (registered at 1 h intervals) after dynamic mechanical solicitation carried out during 48 h, shows the excellent output reliability and no decrease in amplitude with time.

Pulsed laser deposition is a technique used since twenty years ago for the production of nanoparticles films. Laser pulses with a duration in the femtosecond, picosecond and nanosecond range have been employed for material processing as well as for ablation and deposition of semiconductors, superconductive materials, ceramics, magnetic layers and multilayers. Recently, results on the ultra-short pulsed laser deposition (uPLD) revealed this technique as particularly interesting for the deposition of magnetic nanogranular films. This review deals with the innovative findings and the potential developments related to the use of uPLD. The following points are addressed: first, the peculiar shape and orientation of the nanoparticles in the films obtained by the uPLD technique; second, the capability of uPLD to reproduce the stoichiometry in target material in the deposited film; third, the possibility to produce nanogranular amorphous film from polycrystalline target; fourth, the potentiality of uPLD in tailoring the magnetic softness of the film by means of a co-deposition of hard and soft magnetic nanoparticles. Finally, we briefly discuss the potential applications of the uPLD in the production of composite nanogranular films with interesting performances for improved magnetostrictive and magnetoresisitive micro-devices.

The coupling between elastic and magnetic properties of composite materials made of magnetic particles uniformly dispersed into an elastic matrix was revised. The influence of particles content and size was considered. A unified simple model of the direct and inverse elastomagnetic effect was furnished explaining the experimental results in different experimental conditions. Some applications of elastomagnetic materials in both sensors and actuators are reported and their potentiality is discussed. The correlation between strain and electric conduction in this kind of materials is also presented and the first experimental results on this topic are reported.

Starting from the basic phenomena of direct and inverse magnetostriction, the status of art of actual application and material development are critically reviewed. Important developments in noise detection and control are pointed out and several innovations are also reported. On the other hand, the crucial improvements to be performed in material performance, devices techniques and modeling are clearly discussed. In particular the first characterization of a new device, based on a novel composite material made of magnetic particles dispersed in an elastic matrix, able of self-attenuation of vibrations also at the resonance frequency, is reported and discussed. Since some problems in vibration control are related to the induction of a spontaneous acoustic mode in the core of the device used for the oscillations detection and/or attenuation, this new system appears to be very interesting for the researchers community involved in noise control and monitoring.

Femtosecond pulsed laser deposition (fs-PLD) in vacuum has been demonstrated to be a powerful and versatile tool for the production of metal and semiconductor nanoparticle-assembled films. In contrast to ablation with longer laser pulses, namely ns-PLD, where the presence of a high-pressure gas is necessary to obtain nanoparticles (NPs), in fs-PLD the NPs are produced under vacuum as a consequence of decomposition of a target material irradiated by fs pulses. The nanoparticle-assembled films show a structure with agglomerates of NPs, each one formed by closely connected NPs with a significant shape and orientation anisotropy and negligible coalescence, even at high NP volume fractions, though the precise nature of the interface remains uncertain, and an exchange interaction is active among the nearest NPs. The as-deposited mono-component (Fe, Co, Ni,) and bi-component (NiSi, CoCu, FeAg) magnetic films present a high in-plane remanence ratio, relatively low values of the saturation and coercive fields and a steep slope near coercivity. This appears related to the fact that the nanoparticles, coupled by exchange interactions, are effectively single domain and single grain NPs, as observed comparing AFM and X-Ray size evaluations. Furthermore, the exchange interaction between hard magnetic nanoparticles (Terfenol-D) and soft magnetic nanoparticles (Iron) is active in the fs-PLD film, giving a cumulative magnetic response resulting from an average of the properties of the two component phase (exchange-spring magnets). In prospective the striking properties of these nanoparticle-assembled films appear very promising for potential application as nanocomposite permanent magnets and in data storage technology. Finally, the influence of the novel structural conditions on the coupling between strain and magnetization, and/or strain and resistivity, in Co50Fe50 NP films deposited on Kapton substrate, was investigated, thus evidencing novel elastoresistive and elastomagnetic functionalities and evaluating their relative sensitivities.