El Nobel de física i el teu portàtil

El darrer premi Nobel de física s'ha concedit per treballs que han posat les bases per a la fabricació de discs durs cada vegada més petits. Quins són els avenços que ho han fet possible

Albert Fert i Peter Grünberg: Premis Nobel de Física 2007

El descobriment per part d'Albert Fert i Peter Grünberg (Premis Nobel Física 2007) de la magnetoresistència gegant ha obert les portes a l'espintrònica. En aquest article fem una breu revisió de les diferents contribucions experimentals i conceptuals que van fer possible aquell descobriment i n'expliquem els fonaments

The 2016 oxide electronic materials and oxide interfaces roadmap

Lorenz, M. et al.Oxide electronic materials provide a plethora of possible applications and offer ample opportunity for scientists to probe into some of the exciting and intriguing phenomena exhibited by oxide systems and oxide interfaces. In addition to the already diverse spectrum of properties, the nanoscale form of oxides provides a new dimension of hitherto unknown phenomena due to the increased surface-to-volume ratio. Oxide electronic materials are becoming increasingly important in a wide range of applications including transparent electronics, optoelectronics, magnetoelectronics, photonics, spintronics, thermoelectrics, piezoelectrics, power harvesting, hydrogen storage and environmental waste management. Synthesis and fabrication of these materials, as well as processing into particular device structures to suit a specific application is still a challenge. Further, characterization of these materials to understand the tunability of their properties and the novel properties that evolve due to their nanostructured nature is another facet of the challenge. The research related to the oxide electronic field is at an impressionable stage, and this has motivated us to contribute with a roadmap on ‘oxide electronic materials and oxide interfaces’. This roadmap envisages the potential applications of oxide materials in cutting edge technologies and focuses on the necessary advances required to implement these materials, including both conventional and novel techniques for the synthesis, characterization, processing and fabrication of nanostructured oxides and oxide-based devices. The contents of this roadmap will highlight the functional and correlated properties of oxides in bulk, nano, thin film, multilayer and heterostructure forms, as well as the theoretical considerations behind both present and future applications in many technologically important areas as pointed out by Venkatesan. The contributions in this roadmap span several thematic groups which are represented by the following authors: novel field effect transistors and bipolar devices by Fortunato, Grundmann, Boschker, Rao, and Rogers; energy conversion and saving by Zaban, Weidenkaff, and Murakami; new opportunities of photonics by Fompeyrine, and Zuniga-Perez; multiferroic materials including novel phenomena by Ramesh, Spaldin, Mertig, Lorenz, Srinivasan, and Prellier; and concepts for topological oxide electronics by Kawasaki, Pentcheva, and Gegenwart. Finally, Miletto Granozio presents the European action ‘towards oxide-based electronics’ which develops an oxide electronics roadmap with emphasis on future nonvolatile memories and the required technologies. In summary, we do hope that this oxide roadmap appears as an interesting up-to-date snapshot on one of the most exciting and active areas of solid state physics, materials science, and chemistry, which even after many years of very successful development shows in short intervals novel insights and achievements.This work has been partially supported by the TO-BE COST action MP1308. J F acknowledges financial support from the Spanish Ministry of Economy and Competitiveness, through the ‘Severo Ochoa’ Programme for Centres of Excellence in R&D (SEV-2015-0496) and MAT2014-56063-C2-1R, and from the Catalan Government (2014 SGR 734). F.M.G. acknowledges support from MIUR through the PRIN 2010 Project ‘OXIDE’.Peer reviewe

The Shortening of MWNT-SPION Hybrids by Steam Treatment Improves Their Magnetic Resonance Imaging Properties In Vitro and In Vivo

Cabana, Laura et al.Carbon nanotubes (CNTs) have been advocated as promising nanocarriers in the biomedical field. Their high surface area and needle-like shape make these systems especially attractive for diagnostic and therapeutic applications. Biocompatibility, cell internalization, biodistribution, and pharmacokinetic profile have all been reported to be length dependent. In this study, further insights are gotten on the role that the length of CNTs plays when developing novel contrast agents for magnetic resonance imaging (MRI). Two samples of CNTs with different length distribution have been decorated with radio-labeled iron oxide nanoparticles. Despite characterization of the prepared hybrids reveals a similar degree of loading and size of the nanoparticles for both samples, the use of short CNTs is found to enhance the MRI properties of the developed contrast agents both in vitro and in vivo compared to their long counterparts. KeywordsL.C. and M.B. contributed equally to this work. The authors are grateful to Thomas Swan Co. & Ltd for supplying the Elicarb MWNT samples. L.C. acknowledges a CSIC JAE Predoc Fellowship. M.B. is a Marie Curie Fellow. Funding from FP7-ITN Marie-Curie Network programme RADDEL (290023), Biotechnology and Biological Sciences Research Council (BB/J008656/1), Worldwide Cancer Research (12-1054), and Spanish Ministry of Economy and Competitiveness (MAT2014-53500-R and MAT2014-56063-C2-1R) is acknowledged. R.T.M.D. acknowledges funding by The Centre of Excellence in Medical Engineering funded by the Wellcome Trust and EPSRC under Grant No. WT 088641/Z/09/Z. L.C., J.F., and G.T./ ICMAB acknowledge fi nancial support from the Spanish Ministry of Economy and Competitiveness, through the “Severo Ochoa” Programme for Centres of Excellence in R&D (SEV-2015-0496). K.T.A., G.T, and R.T.M.D. thank the members of the EU COST actions TD1004 (Theranostics Imaging and Therapy: An Action to Develop Novel Nanosized Systems for Imaging-Guided Drug Delivery) and TD1007 (Bimodal PET-MRI molecular imaging technologies and applications for in vivo monitoring of disease and biological processes) for useful discussions. The XPS data were acquired at the Laboratorio de Microscopías Avanzadas (LMA) – Instituto de Nanociencia de Aragón (INA) (Spain).Peer reviewe

Polar domain walls trigger magnetoelectric coupling

Interface physics in oxide heterostructures is pivotal in material's science. Domain walls (DWs) in ferroic systems are examples of naturally occurring interfaces, where order parameter of neighboring domains is modified and emerging properties may develop. Here we show that electric tuning of ferroelastic domain walls in SrTiO3 leads to dramatic changes of the magnetic domain structure of a neighboring magnetic layer (La1/2Sr1/2MnO3) epitaxially clamped on a SrTiO3 substrate. We show that by exploiting the resposiveness of DWs nanoregions to external stimuli, even in absence of any domain contribution, prominent and adjustable macroscopic reactions of neighboring layers can be obtained. We conclude that polar DWs, known to exist in other materials, can be used to trigger tunable responses and may lead to new ways for manipulation of interfacial emerging properties

Anisotropic magnetoresistance in an antiferromagnetic semiconductor

arXiv:1303.4704v1.-- et al.Recent studies in devices comprising metal antiferromagnets have demonstrated the feasibility of a novel spintronic concept in which spin-dependent phenomena are governed by an antiferromagnet instead of a ferromagnet. Here we report experimental observation of the anisotropic magnetoresistance in an antiferromagnetic semiconductor Sr2IrO4. Based on ab initio calculations, we associate the origin of the phenomenon with large anisotropies in the relativistic electronic structure. The antiferromagnet film is exchange coupled to a ferromagnet, which allows us to reorient the antiferromagnet spin-axis in applied magnetic fields via the exchange spring effect. We demonstrate that the semiconducting nature of our AFM electrode allows us to perform anisotropic magnetoresistance measurements in the currentperpendicular- to-plane geometry without introducing a tunnel barrier into the stack. Temperature- dependent measurements of the resistance and anisotropic magnetoresistance highlight the large, entangled tunabilities of the ordinary charge and spin-dependent transport in a spintronic device utilizing the antiferromagnet semiconductor.We acknowledge the support from the NSF (Nanosystems Engineering Research Center for Translational Applications of Nanoscale Multiferroic Systems, Cooperative Agreement Award EEC-1160504). We acknowledge partial support from the US Department of Energy (J.H.C., S.S. and R.R.) as well as the SRC-FAME programme through UCLA (C.R.-S.). T.J. acknowledges support from the EU European Research Council (ERC) advanced grant no. 268066, from the Ministry of Education of the Czech Republic grant no. LM2011026, from the Grant Agency of the Czech Republic grant no. 14-37427G and from the Academy of Sciences of the Czech Republic Praemium Academiae. X.M. acknowledges the Grant Agency of the Czech Republic No. P204/11/P339. A.B.S.Peer Reviewe