News and posts
Time: Monday, October 8th, 14:00
Speaker: Theo RASING, Radboud University
The explosive growth of big data and artificial intelligence offers a huge potential for new digital products and unexplored business models. While data has become an indispensable part of modern society, the sheer amount of data being generated every second is breathtaking, both in its scale and in its growth, while the number of devices generating these data is rapidly expanding. This not only pushes current technologies to their limits, but also that of our energy production: our ICT and data centres already consume around 7% of the world’s electricity production and with the growth rate of ICT-technologies, this energy consumption is rapidly becoming unsustainable. In stark contrast, the human brain, with its intricate architecture combining both processing and storing of information, only consumes about 10 Watt of energy while having a similar capacity as a supercomputer consuming around 10 Megawatt.
We try to develop materials and concepts that mimic the efficiency of the brain by combining local processing and storage, using adaptable physical interactions that can implement learning algorithms. We demonstrate, by modelling, that a reconfigurable and self-learning structure can be achieved, which implements the prototype perceptron model of a neural network based on magneto-optical interactions. Importantly, we show that optimization of synaptic weights is achieved by a global feedback mechanism, such that learning does not rely on external storage or additional optimization schemes. For the experimental realization of adaptive synaptic structures, we choose to use optically controllable magnetization in a thin Co/Pt film1, using circularly polarized picosecond2 pulse trains. The combined stochastic/deterministic nature of all-optical switching in this material2 offers the possibility to continuously vary the magneto-optical Faraday rotation with the number of pulses, yielding the necessary ingredient to realize a perceptron-like structure. First results of such a learning structure will be demonstrated.
1. C.-H. Lambert et al, Science 345, 1337 (2014)
2. R. Medapalli et al, Phys. Rev.B 96, 224421 (2017)
20.12.2017 – Job offer: PhD Position in Spintronics in the Institute of Physics at the Johannes Gutenberg-Universität Mainz
Johannes Gutenberg-Universität Mainz, Germany
We are pleased to announce the opening of two PhD positions in theoretical condensed matter in the Institute of Physics at the Johannes Gutenberg-Universität Mainz to work with the spintronics theory groups INSPIRE (Jairo Sinova) and TWIST (Karin Everschor- Sitte) on topics such as antiferromagnetic spintronics, skyrmions, and topological matter. The physics institute and the Spin Phenomena Interdisciplinary Center (SPICE) provides a stimulating environment due to an active workshop program and a broad range of research activities.
The prospective group member must hold a MSc or equivalent diploma. A background in theoretical techniques in condensed matter physics is required. Candidates interested and/or experienced in spintronics, magnetization dynamics, the physics of antiferromagnetics or skyrmions, and micromagnetic modelling are highly suited for this opportunity. Programming experience is desired.
Further information can be found on the websites: https://www.inspire.uni-mainz.de or http://www.twist.uni-mainz.de/
Johannes Gutenberg-Universität Mainz is an equal opportunity, affirmative actions employer in compliance with German disability laws. Women and persons with disabilities are encouraged to apply.
Review of applications begins immediately and will continue until the position is filled. Interested applicants should send a curriculum vitae, a list of publications, and at least two letters of recommendation to email@example.com. When sending applications please use the subject line “Spintronics PhD position application”.
Prof. Jairo Sinova
Head of the group INSPIRE
Director of SPICE
Dr. Karin Everschor-Sitte
Head of Emmy Noether Research Group TWIST
Scientific Coordinator of SPICE
Johannes Gutenberg-Universität Mainz FB 08 – Institut für Physik Staudingerweg 7
Exotic New States in Superconducting Devices: The Age of the Interface
Superconducting material such as a ferromagnet, a topological insulator or a semiconductor, a range of electronic states can be induced which are radically different from either constituent material. To be able to probe these states requires a broad range of expertise, spanning basic materials science to fundamental physics modeling of interfaces and transport behaviour. At this meeting we have the opportunity to bring together scientists working on distinct and overlapping areas, such as superconductivity, magnetism, topological materials, quantum computing, and spin-electronics. This science community will have an opportunity to appreciate how these different transport phenomena are linked conceptually and thereby stimulate further understanding particularly with respect to realising useful devices with unique properties for spin-electronics and quantum computing.
Insulator spintronics – strong-coupling, coherence and entanglement
Magnetic insulators are extremely versatile materials. They’re used for fundamental research into magnetism and in real world devices. They have become a vital tool across many research disciplines to the extent that they are now micro-scale laboratories in their own right. The lack of charge currents in these materials allows for a very controlled environment where pure spin currents can flow and single magnons can be excited. However, nature is not so kind and the majority of magnetic insulators are a complex class of materials with many complications which must be understood.
This SPICE Young Research Leaders Workshop aims to bring together young scientific leaders who are interested in how magnetic insulators can be used to push the frontier of our understanding of basic science as well as technological frontiers such as spintronics and quantum computing. Specifically, this workshop will bring together researchers from the fields of insulator spintronics, magnon-polaritons and quantum magnetism to exchange ideas and discuss new ways in which magnetic insulators can be applied to fundamental research and applications.
In recent years the concepts of topology have entered strikingly all areas of physics, interlinking many previously unrelated areas of research. New topological materials and topological phases with exotic properties have been discovered at a rapid pace. However, these new phases are still being studied primarily within their own sub-disciplines of condensed matter, with not enough interaction among them to explore new emerging paths to hybrid and multifunctional advanced materials.
The workshop "Topology Matters" aims to bring together the top scientists in the fields of spintronics, superconductivity, topological insulators, and multiferroics in order to explore their connections via topology. The rapid developments in each of these fields, and the emerging importance of topology in all of them makes this workshop very timely.
Modern scientific research in condensed matter physics has been marked by a newly perceived role of the quantum nature of a spin in the most basic properties of materials. This breakthrough reflected itself in a new comprehension of fundamental physical symmetries, the concept of the topological classification of the quantum states properties, some of which are close to practical applications.
The aim of the SPICE workshop “Spin Dynamics in Dirac System” is to offer a platform for the knowledge exchange between diverse novel condensed matter domains such as topological insulators and superconductors, Weyl physics, topological Josephson junctions, spintronics in graphene, spin valves, spin-logic devices, quantum magnetism, spin lattices, frustrated magnets, spin liquids, non-trivial spin states, etc.
In contrast to equilibrium quantum systems, which exist in just a tiny corner of an immense configuration space, non-equilibrium quantum many-body systems can access the totality of configuration space and represent a rich resource for novel quantum states, including light-induced quantum-coherent phases of matter, topological phases and spin textures in solids and cold atom systems. Non-equilibrium many-body quantum dynamics is perhaps the last frontier in physics, where even the basic understanding is still lacking and a number of outstanding fundamental questions are wide open. However, there has been much recent progress in exploring these fundamental aspects on both theoretical and experimental sides.