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Nanoporous materials represent a unique class of materials, given to their unforeseen magnetic, mechanical, optical and catalytic properties arising from their network of pores and ligaments. Here a polycrystalline thin film of FePd is considered as a starting system, in which the porosity is induced via dealloying. This process determines the removal of iron from the alloy and the diffusion of palladium on the surface, which in turn influences the evolution of the material’s composition, magnetic properties and optical properties. In addition, from the magnetic point of view, the material acquires a more isotropic behaviour while the magnetic moment decreases due to the removal of iron. In the same way, there is an improvement of the surface enhanced Raman scattering as the dealloying proceeds, due to the formation of clusters of palladium on the surface. This mixture of optical and magnetic properties, combined with its high corrosion resistance and biocompatibility, gives the system a strong multifunctional connotation, paving the way for new applications, ranging from magnetic trapping to detection of low concentration of molecules.

Measurement of thin film magnetostriction is a challenging task, as magnetostrictive material deformations in parts per million, in conjunction with materials at small dimensions, require high precision, often with dedicated set-ups, for reproducible results. We have developed a novel approach employing a commercial atomic force microscope (AFM) with attached electromagnets. Magnetostriction measurements are demonstrated on 50–500 nm thick Fe81Al19 films sputter deposited directly on high aspect ratio commercial AFM micro-cantilevers. A magnetostrictive deflection of the cantilever bimorph translates into a deflection force acting in a contact mode measurement, which is interpreted and recorded as a change in height. For determination of the magnetostriction coefficient λ s , we have developed a modified version of the equation for the magnetostrictive deflection of a cantilever bimorph by Guerrero and Wetherhold, taking into account long-range attractive forces acting during contact mode AFM measurements in air. The sub-atomic precision of the AFM, combined with the widespread availability of all components and the simple set-up, makes the measurement of magnetostriction on films of just a few tens of nanometers thickness easily accessible.