Eligible candidates must fulfill all the requirements necessary to apply for the PREDOC BERRI Fellowship program of the Department of Education of the Basque Government. Note that candidates must be currently resident in the Basque Country since at least 1 January 2018.
The PhD projects will be related to the current interests of the research groups at nanoGUNE:
- Nanomagnetism - Andreas Berger and Paolo Vavassori
- Nanooptics - Rainer Hillenbrand
- Self-Assembly - Alexander Bittner
- Nanobiomechanics - Raul Perez-Jimenez
- Nanodevices - Luis Hueso and Felix Casanova
- Electron Microscopy - Andrey Chuvilin
- Theory - Emilio Artacho
- Nanomaterials - Mato Knez
- Nanoimaging - Jose Ignacio Pascual
- Nanoengineering - Andreas Seifert
The PREDOC BERRI call of the Basque Government for 2018-2019 is now open and interested candidates are welcomed to submit their application together with their CV and Academic Record to the Group Leader of their interest no later than 15 June 2018.
All the information about the fellowships is available at these links:
Schematic illustration of gold-magnet hybrid nanostructures illuminated by a laser (red). Due to the polarization-dependent excitation of the plasmonic resonance in the gold part, orthogonal nanoelements can be heated independently. The magnetic moment of the hot magnets (front) can be reversed more easily, resulting in a narrower field-driven magnetic hysteresis loop (left) compared to that of the cold magnets (right).
Single-domain nanoscale magnets interacting via contactless magneto-static interactions are key metamaterials for magnetic data storage devices, for low-power information processing, and to study collective phenomena in so-called artificial ices. These magnetic metamaterials are fabricated using electron-beam nano-lithography where any desired two-dimensional arrangement of thin-film magnetic elements with dimensions of a few hundred nanometers can be designed.
The functionality of such magnetic metamaterials is determined by the capability to reverse the net moment of each nanomagnet to minimize the overall mutual magnetostatic interactions, which happens more quickly at elevated temperatures. Over the years, different heating schemes have been employed to drive networks of interacting nanomagnets to an equilibrium state, ranging from thermal annealing of stable magnets to the fabrication of rapidly-fluctuating ultrathin superparamagnetic elements. As of today, thermal excitation of artificial spin systems is achieved by thermal contact to a hot reservoir, either by heating the entire underlying substrate, or by an electrical current in a conductive wire nearby. All these approaches are energetically inefficient, spatially non-discriminative, and intrinsically slow, with time scales of seconds to hours, making it difficult to reach a true equilibrium state in extended frustrated nanomagnetic lattices. Furthermore, for implementation in devices of magnetic metamaterials, e.g. magnonic crystals and nanomagnetic logic circuits, global heating lacks the control, spatial discrimination, and speed required for integrated operation with CMOS technology.
Applying a hybrid approach that combines a plasmonic nanoheater with a magnetic element, in this work the authors establish the robust and reliable control of local temperatures in nanomagnetic arrays by contactless optical means. Here, plasmon-assisted photo-heating allows for temperature increases of up to several hundred Kelvins, which lead to thermally-activated moment reversals and a pronounced reduction of the magnetic coercive field. Furthermore, the polarization-dependent absorption cross section of elongated plasmonic elements enables sublattice-specific heating on sub-nanosecond time scales, which is not possible with conventional heating schemes. The authors experimentally quantify the optical and magnetic properties of arrays of single hybrid elements as well as vertex-like assemblies, and present strategies how to achieve efficient, fast, and selective control of the thermally-activated magnetic reversal by choice of focal point, pump power, light polarization, and pulse duration.
Therefore, the development of efficient non-invasive plasmon-assisted optical heating of nanomagnets allows flexible control of length and time scales of the thermal excitation in magnetic metamaterials. This enables deeper studies of equilibrium properties and emergent excitations in artificial spin systems, as well as open doors for the practical use in applications such as low-power nanomagnetic computation.
Selective and fast plasmon-assisted photo-heating of nanomagnets
Matteo Pancaldi, Naëmi Leo and Paolo Vavassori
This work was supported by the Ministerio de Economía y Competitividad under the Maria de Maeztu Units of Excellence Programme – MDM-2016-0618 and the Project FIS2015-64519-R, as well as from the European Commission under the Project H2020-FETOPEN-01-2016-2017 “FEMTOTERABYTE” (project no. 737093).
As a collective effort of leading experts from 10 different countries, the 2020 Magnetism Roadmap, which is an Open Access article, is intended to provide a reference point and guide to the interested community on relevant and emerging research directions in modern magnetism. The article consists of 14 sections, each written by an expert in the field and addressing a specific subject on two pages. Contributing authors include: E.Y. Vedmedenko, R.K. Kawakami, D.D. Sheka, P. Gambardella, A. Kirilyuk, A. Hirohata, C. Binek, O. Chubykalo-Fesenko, S. Sanvito, B.J. Kirby, J. Grollier, K. Everschor-Sitte, T. Kampfrath, C.-Y. You and A. Berger.
Following the success and relevance of the 2014 and 2017 Magnetism Roadmap articles, this 2020 Magnetism Roadmap edition takes yet another timely look at newly relevant and highly active areas in magnetism research. A different group of experts has again been selected for this article, representing both the breadth of new research areas, and the desire to incorporate different voices and viewpoints. Despite its two-page limit for each subject, the most relevant and key aspects of each field are briefly described, which enables the Roadmap as whole to give its readers an initial overview of and outlook into a wide variety of topics and fields in a fairly condensed format. Correspondingly, the Roadmap pursues the goal of giving each reader a reference frame of relevant and current topics in modern applied magnetism research.