Reconfigurable Mechanical Anisotropy and Super-Magnetostriction in Self-Assembled Magnetic Superstructures
Our group, in collaboration with NTNU-Trondheim and the University of Sydney, is contributing to the emerging field of enhanced mechanical properties in self‐assembled superstructures of magnetic nanoparticles. In two papers recently published in the high-IF journals Advanced Functional Materials and Advanced Science, we have demonstrated how the mechanical properties of self‐assembled magnetic nanocubes can be controlled by the nanoparticle magnetocrystalline anisotropy (MA) and the superstructure shape anisotropy. A low MA‐to‐dipolar energy ratio, as found in iron oxide systems (superparamagnetic at RT), favours isotropic mechanical superstructure stabilization, whereas a high ratio yields magnetically blocked nanoparticle macrospins which can give rise to metastable superferromagnetism, as expected in cobalt ferrite simple cubic supercrystals. Such full parallel alignment of the particle moments is shown to induce mechanical anisotropy, where the superior high‐strength axis (as that present naturally in wood) can be remotely reconfigured by means of an applied magnetic field (see left figure). The new concepts developed here pave the way for the experimental realization of smart magneto‐micromechanical systems (based, e.g., on the permanent super‐magnetostriction effect illustrated in the right figure here) and inspire new design rules for applied functional materials.

Benito Santos, new PhD in Apnano

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, new member of ApNano

 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!


PhD Position in Magnetic Nanoparticles

 We announce a 4 years PhD grant (+ travel allowances) to work in the Instituto Regional de Investigación Científica Aplicada (IRICA) in the Ciudad Real campus under the supervision of Prof. Chris Binns.

Project: The student will contribute to the set up and exploitation of a new high-vacuum facility to prepare liquid dispersions of heterostructured magnetic nanoparticles for biomedical applications. In parallel, the student will be introduced and take part in ongoing studies on the magnetism of thin nanoparticle stripes and self-assembled systems.
Qualifications: Candidates must have a Master’s degree in Physics, Materials Science or Engineering by 15/Sept/2020 in order to enroll in UCLM’s Escuela Internacional de Doctorado.
Evaluation based on: Skype/on-site interview, academic record, English level (Spanish not mandatory but valuable), lab experience, programming, …
Contact: Please send your CV and motivation letter (English or Spanish) to christopher.binns@uclm.es and joseangel.toro@uclm.es

Deadline for interviews:  15/May/2020.

Starting Date: Fall/2020.

SQUIDing and skiing with the ApNANO group

Verner Håkonsen (in the picture with Jose Angel), from the NTNU Nanomechanical Lab at Trondheim (Norway), has been with us in Ciudad Real for the last 10 days to further our collaboration on superstructures of Fe oxide nanocubes (see three posts below for a summary of our recent paper in AFM). As you can see, we also managed to find some time for what would be a glorious day of skiing in Sierra Nevada.

Chris Binns will join the ApNANO group in February-2020

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!

Can we go together? Individual vs Collective Behavior in Binary systems

 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. 

Magnetically Enhanced Mechanical Stability in Self-Assembled Superstructures of Nanocubes

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.

Spring Training at ApNANO for Francesca and Chiara

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!

Alberto López Ortega new research member at the ApNANO group

Alberto López Ortega has joined the Applied Nanomagnetism group as an assistant professor. He will teach at the Escuela de Ingeniería Industrial y Aeroespacial in Toledo. He obtained his Degree on Chemistry at the Universitat de Barcelona in 2007 and his PhD in Materials Science at the Universitat Autònoma de Barcelona in 2012 (with an Outstanding Award). He subsequently spent three years as a postdoctoral researcher at the Univerità degli Studi di Firenze (Italy) and came back to Spain with a Juan de la Cierva – Incorporación fellowship to the research center CIC-Nanogune (San Sebastián, Spain), where he spent another three years.

In particular, Alberto’s expertise in the synthesis of magnetic nanostructures by colloidal and electron beam lithography methods (with special emphasis in the development of complex hybrid bi-magnetic nanoparticles and magneto-plasmonic heterostructures) is a great new asset for our group. You are most welcome, Alberto!