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A frontier topic in nanotechnology is the realization of multifunctional nanoparticles (NPs) via the appropriate combination of different elements of the periodic table. The coexistence of Fe and Ag in the same nanostructure, for instance, is interesting for nanophotonics, nanomedicine, and catalysis. However, alloying of Fe and Ag is inhibited for thermodynamic reasons. Here, we describe the synthesis of Fe-doped Ag NPs via laser ablation in liquid solution, bypassing thermodynamics constraints. These NPs have an innovative structure consisting of a scaffold of face-centered cubic metal Ag alternating with disordered Ag–Fe alloy domains, all arranged in a truffle-like morphology. The Fe–Ag NPs exhibit the plasmonic properties of Ag and the magnetic response of Fe-containing phases, and the surface of the Fe–Ag NPs can be functionalized in one step with thiolated molecules. Taking advantage of the multiple properties of Fe–Ag NPs, the magnetophoretic amplification of plasmonic properties is demonstrated with proof-of-concept surface-enhanced Raman scattering and photothermal heating experiments. The synthetic approach is of general applicability and virtually permits the preparation of a large variety of multi-element NPs in one step.[Figure not available: see fulltext.

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Utilization ofin situ/operandotechniques for establishing the chemical/structural changes induced on Co–Fe spinels that determine their OER durability.

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The reliable determination of bioapatite crystallinity is of great practical interest, as a proxy to the physico-chemical and microstructural properties, and ultimately, to the integrity of bone materials. Bioapatite crystallinity is used to diagnose pathologies in modern calcified tissues as well as to assess the preservation state of fossil bones. To date, infrared spectroscopy is one of the most applied techniques for bone characterisation and the derived infrared splitting factor (IRSF) has been widely used to practically assess bioapatite crystallinity. Here we thoroughly discuss and revise the use of the IRSF parameter and its meaning as a crystallinity indicator, based on extensive measurements of fresh and fossil bones, virtually covering the known range of crystallinity degree of bioapatite. A novel way to calculate and use the infrared peak width as a suitable measurement of true apatite crystallinity is proposed, and validated by combined measurement of the same samples through X-ray diffraction. The non-linear correlation between the infrared peak width and the derived ISRF is explained. As shown, the infrared peak width at 604 cm−1 can be effectively used to assess both the average crystallite size and structural carbonate content of bioapatite, thus establishing a universal calibration curve of practical use.