Raúl López Martín has presented the early results of his research work entitled “Exchange bias studied by protected-annealing experiments in maghemite-core and iron-core nanoparticles” at the 5th Young Researchers in Magnetism (YRinM). In this work, the evolution of the exchange bias field coming from the surface spin disorder shell of magnetic silica-coated nanoparticles upon annealing is studied. Magnetic as well as structural measurements are key to understand the influence of the annealing temperature on the magnetic behavior of these nanoparticles.

Very nice talk, Raúl. Keep going!

Elena H. Sánchez defends her PhD

Elena successfully defended her thesis entitled “Magnetic Anisotropy Effects in Nano-Undulated Films and Strongly Interacting Nanoparticle Assemblies” in Toledo last March. After presenting a difficult summary of her great job on a variety of nanomagnetism topics over the last four years, she was awarded with a Cum Laude qualification and the International Mention (after predoctoral stays in Liverpool and Cagliari).

Many congratulations, Elena, best of luck in your postdoctoral career, and keep in touch!!

Benito Santos, with a PhD from the Universidad Autónoma de Madrid (2011), has just joined the group. Benito worked as a postdoc at the nanospectroscopy line of the Elettra synchrotron, where he studied the structural, reactivity and magnetic properties of very thin metallic films by combining X-ray spectroscopy and electron microscopy and diffraction (LEED, LEEM) analytical methods. He’s also spent research periods in Berkeley Lab, Sandia National Lab and the University of New Hampshire, and used STM and XPS for surface and chemical characterization.

Benito will be involved in the growth and the structural and magnetic characterization of metallic nanoparticles by gas-phase synthesis methods. Welcome to Ciudad Real!

Raúl López Martín has just joined the group to pursue a PhD with 4-year grant he got in the last call of UCLM’s “Plan Propio”. Raúl holds a double degree in Physics and Materials Engineering and a Msc in ‘Science and Technology of New Materials’ (both at the University of Seville). The topic of his thesis will be related with the gas-phase synthesis of magnetic core/shell particles for biomedical and energy applications. Welcome, Raúl!

Chris Binns, Emeritus Professor of Nanoscience at the University of Leicester, was in Ciudad Real last October to sign his “Beatriz Galindo distinguished researcher” contract and will join the ApNano group in February/2020. The research project that won him the senior Beatriz Galindo grant (one of only 100 nationwide) is based on the gas-phase synthesis of magnetic hydrosols for biomedical applications. We look forward to implementing it and, generally, to benefitting from Chris’s large experience in nanoparticle deposition and characterization. Bienvenido a La Mancha, Chris!

The journal Chemistry of Materials has just accepted for publication our study (in collaboration with long-term collaborators) on the magnetism of random binary compacts comprising two uniformly mixed populations of soft and hard nanoparticles (preprint here). It turns out that the answer we have found for the question above is «it depends where!», as we inform directly in the title of the paper: «Simultaneous individual and dipolar collective properties in binary assemblies of magnetic nanoparticles». We have shown how compact mixtures may be employed as a tool to test or, rather, to define the collective character of a given magnetic property as that resulting in the collapse of the individual features caused by strong enough interactions. Crucially, such collective character must, in general, be ascribed to specific properties and not to the system as a whole. 

The ApNano group has taken part, in collaboration with researchers from the Norwegian University of Science and Technology and from the University of Sydney, in an investigation of magnetically enhanced mechanical stability in self-assembled nanostructures. The results, which have just been published in Advanced Functional Materials, combine Monte Carlo simulations, magnetic characterization and electronic microscopy to conclude a significant increase in cohesive energy from the magnetostatic interactions between magnetite nanocubes assembled in dense superstructures. This increase depends strongly on the size of the assembly. The discovery of this effect opens new possibilities in size-controlled tuning of superstructure properties, thus contributing to the design of next-generation self-assembled materials with simultaneous enhancement of magnetic and mechanical properties.

Chiara Olla (University of Cagliari) and Francesca Airaldi (University of Genoa) just left us after spending three months in our lab as Erasmus+ trainees. Both will next defend their Master degrees projects with new data and training in magnetometry and X-ray diffraction. We learnt with Chiara about the magnetism and structure of luminescent carbon dots doped with gadolinium synthesized in a mesoporous silica matrix, whereas Francesca studied

magnetic properties of different bi-magnetic core/shell ferrite nanoparticles. Both will pursue PhD studies back in Italy, best of luck with it!

In collaboration with Instituto Rocasolano (CSIC, Madrid), who provided laser-irradiated undulated polymer substrates, we have succeeded in the preparation of nanoparticle stripes by self-shadowing deposition of gas-aggregated Pd particles. This novel type of nanostructure, with promising anisotropic properties, was one of the main objectives of our ongoing national project. The synthesis procedure, as well as optical, electrical and hydrogen-detection properties, have been submitted to the journal Applied Surface Science.