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Light wave dynamic control of spins
The magnetic moment of matter has only been able to be influenced up to now by a light and magnetism-linked process and roundabout way by means of magnetic fields, which is why magnetic switching takes that much longer and at least several hundred femtoseconds. A consortium of researchers from the Max Planck Institutes for Quantum Optics and for Microstructure Physics, the Max Born Institute, the University of Greifswald and Graz University of Technology have only now been able to manipulate the magnetic properties of a ferromagnetic material on a time scale of electrical field oscillations of visible light – and thus in sync with the electrical properties – by means of a few cycle pulse. This influence was able to be accelerated by a factor of 200 and was measured and represented using time-resolved attosecond spectroscopy. In attosecond spectroscopy, magnetic materials are bombarded with ultra-short laser pulses and electronically influenced. “The light pulses set off an intrinsic and usually delaying process in the material. The electronic excitation is translated into a change in magnetic properties,” explains Martin Schultze professor at the Institute of Experimental Physics at TU Graz. Due to the combination of a ferromagnet with a non-magnetic metal, the magnetic reaction in the described experiment, however, is brought about as fast as the electronic one. “By means of the special constellation, we were optically able to bring about a spatial redistribution of the charge carrier, which resulted in a directly linked change in the magnetic properties,” says Markus Münzenberg. Together with his team in Greifswald, he developed and produced the special material systems. As initial step towards coherent magnetism, the researchers show in their measurements that the observed process runs coherently and can be controlled by the interface: this means the quantum mechanical wave nature of the moving charge carriers is preserved. Sangeeta Sharma, researcher at the Max Born Institute in Berlin who predicted the underlying process using time resolved density functional theory, is impressed: “We are expecting a significant development boost from this for all applications in which magnetism and electron spin play a role.”
Press release more...
Magnetische Wirbel treffen auf Topologie
Die Erzeugung und Manipulation von magnetischen Skyrmionen in Nanostrukturen ist Ziel eines neuen Schwerpunktprogramms „Skyrmionics ─ Topological Spin Phenomena in Real-Space for Applications” (SPP 2137) der Deutschen Forschungsgemeinschaft (DFG). Die Physiker Prof. Dr. Markus Münzenberg und Dr. Christian Denker und der Mathematiker Prof. Dr. Konrad Waldorf von der Universität Greifswald sowie Prof. Dr. Jeffrey McCord von der Universität Kiel sind mit dabei. Ihr Projekt „Erzeugung, Manipulation und Wechselwirkung von magnetischen Skyrmionen“ wird in den nächsten drei Jahren mit einer halben Million Euro gefördert. Fernziel dieses Forschungsprojekts ist dieEntwicklung von Anwendungen zum Beispiel in der Informationstechnologie.
In dem Projekt „Erzeugung, Manipulation und Wechselwirkung von magnetischen Skyrmionen“ sollen Skyrmionen in einem sogenannten Schieberegister in einer zweidimensionalen Anordnung und unter definierten Randbedingungen untersucht werden. Das Schieberegister wird lithografisch erzeugt: Mit Kontakten zum Verschieben der Skyrmionen und zum Auslesen werden nanostrukturierte magnetische Tunnelelemente in den Skyrmionen-Film integriert. In dem hier geplanten Schieberegister werden nicht die Bildinformationen, sondern die Skyrmionen verschoben, um ihre komplexen Wechselwirkungen zu untersuchen. Die Ergebnisse lassen sich anschließend mit den Vorhersagen der Topologie vergleichen. Ziel ist es, die magnetischen Solitonen-Wirbel besser zu verstehen, um langfristig in der Informationstechnologie neuartige Datenspeicher oder komplexe, selbstlernende Computer zu entwickeln.
Das Gebiet der Topologie wurde Mitte des 18. Jahrhunderts von dem Mathematiker Leonhard Euler entwickelt. Ein weiterer wichtiger Mathematiker auf dem Gebiet der Topologie war Felix Hausdorff, der auch an der Universität Greifswald lehrte.
Link zur vollständigen Pressemitteilung Uni Greifswald: https://www.uni-greifswald.de/universitaet/information/aktuelles/detail/n/magnetische-wirbel-treffen-auf-topologie-forschungsprojekt-gestartet/
Der Natur auf die Finger schauen - Einzigartiges Hochleistungs-Elektronenmikroskop für die Forscher im Land
Völlig neue Einblicke in die Welt der Atome und Moleküle gewinnen die Wissenschaftler des Departments Leben, Licht und Materie der Universität Rostock. Die Grundlage bildet eine Förderung in Höhe von 3,6 Mio Euro durch den Bund und das Land Mecklenburg-Vorpommern für ein neuartiges Elektronenmikroskop. Damit wird es erstmals möglich, Untersuchungsobjekte im flüssigen oder gasförmigen Zustand auf atomarer Ebene live zu verfolgen. So können kleinste Veränderungen in lebenden biologischen Zellen im Kontakt mit Nanoteilchen hochaufgelöst beobachtet werden. Mit dem neuen Hochleistungs-Elektronenmikroskop ist sogar die Abbildung einzelner Atome möglich, damit kann beispielsweise die Wirkung von Katalysatoren auf chemische Reaktionen direkt verfolgt werden, genauso wie Vorgänge der Strukturbildung von Leichtbauwerkstoffen.
Greifswalder Konsortiumsmitglieder des Instituts für Physik sind daran beteiligt, um unter ultrakurzzeit Laseranregung im Elektronenmikroskop, spintronische Bauelemente auf atomarer Skala besser zu verstehen.
Pressemitteilung Uni Rostock: https://www.uni-rostock.de/universitaet/aktuelles/pressemeldungen/detailansicht/n/der-natur-auf-die-finger-schauen/
Paper out: Large magneto-Seebeck effect in magnetic tunnel junctions with half-metallic Heusler electrodes
In a collaboration between Universities of Bielefeld, Greifswald, Gießen and IFW Dresden, we found another class of materials, that may bring the spincaloritronics of magnetic tunnel junctions closer into praxis. In the study, headed by Alexander Böhnke and Ulrike Martens, in a thight collaboration between Bielefeld and Greifswald, it was demonstrated that the voltages can be tenfold increased towards a millivolt in such tiny junctions, when they in the center of the laser focus. Key are magnetic tunnel junctions with a Heusler based electrode. Heusler materials have a specific band structure that boosts the effect an makes them interesting for spintronics. Magnetism in this class of materials has been measured first in Greifswald (1903 by Richarz). This project was part of the DFG - SPP 1538: "Spin Caloric Transport (SpinCaT)" that endend this year.
A. Boehnke, U. Martens, C. Sterwerf, A. Niesen, T. Huebner, M. von der Ehe, M. Meinert, T. Kuschel, A. Thomas, C. Heiliger, M. Münzenberg, G. Reiss, Nature Comm. 8, 1626 (2017).
Read more "News Uni Greifswald" more...
Paper out: Magnetisation switching of FePt nanoparticle recording medium by femtosecond laser pulses
In a collaboration between Universities of Uppsala, Konstanz, Kiel, Madrid and Western Digital, we lifted the mystery of all-optical manipulation of the magnetization of FePt recording media. Today, FePt nanograins are developed, because of their large magnetic anisotropy, resulting in a high thermal stability even for a few nanometer sized grains, arising in their high coercive field of more than 4 Tesla. They are currently developed further for heat assisted magnetic recording. Our collaboration showed that different steps are important, from ab-initio calculations of the light induced magnetization up to the correct thermal description of the spin ensemble. That shows again the complexity of ultrafast magnetization dynamics, and that there is no unique process for describing ultrafast magnetism. Our calculations for each grain entered into a simple rate model that can explain the switching statistics. To date multiple laser pulses are needed to get a decent writing success. With our single shot experiments compared to the calculations, we can make now predictions for the boundary condition for single-shot laser writing of magnetic bits in the future.
R. John, M. Berritta, D. Hinzke, C. Müller, T. Santos, H. Ulrichs, P. Nieves, J. Walowski, R. Mondal, O. Chubykalo-Fesenko, J. McCord, P. M. Oppeneer, U. Nowak, M. Münzenberg, Sci. Rep. 7, 4114 (2017).
Online publication date: 23-Jun-2017.
Youth and Childrens University Eberswalde and on the Cover of Physical Review Letters
Was ist Nano? Vortrag an der „Jugend – und Kinder Uni“ Eberswalde
Was ist Nano? Prof. Markus Münzenberg hält einen Vortrag zum Thema „Was ist Nano?“. Der Vortrag ist im Rahmen der „Jugend – und Kinder Uni“ vom 14. bis 17. März 2017 an der HNE Eberswalde, organisiert von der Bürgerstiftung Barnim Uckermark. Der Vortrag soll Einblicke liefern für Fünft- bis Sechstklässler in die Nanometer Längenskala und was in diesem Nanokosmos für Effekte auftreten. Ein Nanometer sind ist ein 1/ 1 000 000 000tel Meter. In der Vorlesung werden wir diese Atome in einem Experiment ‚sehen‘.
On the cover of Physical Review Letters
Our work on femtosecond laser generated magnetic vortex structures made it on the cover of Physical Review Letters in the first week of March. We show that strong quenching allows to stabilizes a metastable vortex-antivortex state in thin magnetic films. They are created pairwise. This experiment is part of a collaboration with the University of Göttingen. They were initiated in collaboration with Prof. Claus Ropers und Dr. Sascha Schäfer at our time in Göttingen, establishing an Ultrafast Transmission Electron Microscope (UTEM) at the Göttingen Campus.
Publication: Link to the cover and article http://journals.aps.org/prl/issues/118/9
New paper out in Nature Communications on ultrafast photocurrents
Transient photocurrents can be driven by light. Their nature is still under discussion. To better understand the underlying mechanisms, the current gives insight into the microscopic transport processes. We identify an ultrafast charge transfer along the Se–Bi bonds and also a contribution of a photon-helicity-dependent photocurrent. However, this current is be orders of magnitude smaller than expected from generation scenarios based on asymmetric depopulation of the Dirac cone.
See full research paper
Ultrafast photocurrents at the surface of the three-dimensional topological insulator Bi2Se3
L. Braun, G. Mussler, A. Hruban, M. Konczykowski, M. Wolf, T. Schumann, M. Münzenberg, L. Perfetti, T. Kampfrath, Nature Comm. 7, 13259 (2016).
New papers on ultrafast spin dynamics out as arxiv preprints
All-optical writing of FePt nanograins: in an international effort, together with Universities of Konstanz, Uppsala, Kiel, CISC Madrid, Göttingen, ICCRAM and Western Digital we develope an multiscale understanding of helicity dependent switchingmore...
R. John, M. Berritta, D. Hinzke, C. Müller, T. Santos, H. Ulrichs, P. Nieves, J. Walowski, R. Mondal, O. Chubykalo-Fesenko, J. McCord, P. M. Oppeneer, U. Nowak, and M. Münzenberg, Magnetization switching of FePt nanoparticle recording medium by femtosecond laser pulses, arXiv:1606.08723.
20 years of ultrafast dynamics, ready for applications. What do we know and where do we stand? A perspective of the field more ...
J. Walowski and M. Münzenberg, Perspective: Ultrafast magnetism and THz spintronics, arXiv:1606.08725.
Symposium „Spins, Waves and Interactions“ –
Spins and spin waves for future information technologies, Networking of researchers in Greifswald. The topic „Spins, Waves and Interactions“ is the headline for a meeting 1.-2. September in Greifswald, to discuss new developments and trends in spintronics.
This year, the workshop is generously funded by the Alfried Krupp Kolleg foundation, Greifswald.
On two days from Tuesday to Friday at the Alfried Krupp Wissenschaftskolleg renowed speakers will give their presentations. This time as international speaker from Tohoku University, Sendai, Japan, Joseph Barker will talk about THz dynamics of spin waves.
The workshop is hosted for a third time in the maritime atmosphere of Greifswald, city of the Hanse and university since 1456, place for networking and a look into technological path for the future.
We welcome interested young researchers in the field, please see the conference announcement and registration form.
For further information see the conference website with program, available soon, and detailed information more ...
We are seeing forward to welcome you here!
Andy Thomas and Markus Münzenberg
New broadband THz emitter
Terahertz waves offer numerous applications in ultrafast science. However, thegeneration of such radiation by a low-cost source has remained challenging. Physicists from an international collaboration including theFritz-Haber Institute (Berlin), the Johannes-Gutenberg University (Mainz), the Ernst-Moritz-Arndt University (Greifswald), Forschungszentrum Jülich in Germany and research institutes in France, Sweden and the United States have now realized a new concept for the generation of terahertz waves using spintronic materials.
In contrast to previous designs, their emitters consist of thin metal films and take advantage of the spin rather than only the charge of the electron. Following this approach, they developed broadband emitters fully covering the 1-to-30-THz range, while at the same time being simple designed and compact. Compact, because it is based on spin-orbit effects on femtosecond time scales converting the spin current into a THz emitting charge current on few nanometer lenght scales more...
Read the press release (German):23.05.2016 Neuartige Terahertz-Quelle öffnet Weg zu breiteren Anwendungsmöglichkeitenmore ...
Kinder- und Jugend-Universität 2016
Ein Besuch in unseren Laboren für Kinder am 19.05.2016 und 20.05.2016: "Schwingungen der Melone" Was sind Schwingungen? Ein Einlick in die Bestandteile die unser Leben bestimmen - die Moleküle - und liefert einen Einblick in den Aufbau der Materie. "3D Laserlithografie - Nanometer Skulpturen in der Forschung" Mit der Laserlithografie lassen sich dreidimensional Strukturen für die Forschung herstellen. Es wir ein Einblick gegeben in die Forschung in einem Reinraum, Herstellung von Computerchips und dem Leben im Mikrokosmos.
Das volle Programm der Kinder- und Jugenduni more …
NDR Nordmagazin, Tuesday 22.12., 19:30
We are on TV –
NDR magazin made a report on new equipment at the physics institute (Tuesday 22.12, 19:30 Nordmagazin). Link to the contribution NDR Mediathekmore ...
Press release Wieck bridge and three-dimensional laserlithography more …
Wieck drawbridge in nano: New equipment allows to fabricate three dimensional objects with a resolution of 150nm.
As a test object we fabricated the dutch style drawbridge in the fisher village Wieck, a Greifswald local landmark (original on Wiki). The process works with pulsed laser writing by two-photon laser polymerization. This serves in the future as a platform for nanostructurization of spintronic devices (see A. Boehnke, et al., Sci. Rep. 5, 8945 (2015)), but also to study nanobiomechanics (see R. Palankar et al., Adv. Healthc. Mater.,(2015)). Read the full press release more ...
Schematics of photon induced spin polarization
New publication out: Coherent spin dynamics in Topological Insulators
What happens if a Topological Insulator is driven with circularly polarized photons? In Topological Insulator spin-currents are connected with their surface states. In our research we could identify the origin of a recently seen spin-signal present at the ultrafast time scale. It originates from a coherent spin-polarization.
Read article: Coherent ultrafast spin-dynamics probed in three dimensional topological insulators, F. Boschini et al. Scientific Reports 5, 15304 (2015).
Symposium „Spins, Waves and Interactions“ – Spins and spin waves for future information technologies, Networking of researchers in Greifswald
The topic „Spins, Waves and Interactions“ is the headline for a meeting 9.-11. September in Greifswald, to discuss new developments and trends in spintronics. On two days from Tuesday to Friday at the Alfried Krupp Wissenschaftskolleg renowed speakers will give their presentations. This time as international speakers from Tohoku University, Sendai, Japan, Shunsuke Fukami (Center for Spintronics Integrated Systems), Masahiro Yamashita (Department of Chemistry), and Shigemi Mizukami (Advanced Institute for Materials Research), will talk on spin-orbit torques, organic spintronics and THz dynamics of spin waves. The workshop is hosted for a second time in the maritime atmosphere of Greifswald, city of the Hanse and university since 1456, place for networking and a look into technological path for the future. We hope to establish this meeting as regularly event for young researchers. The workshop will start with a joint dinner Wednesday and informal meeting. Feel free to join from at around 7pm to 11pm, location Theatercafe (located in the Theater Vorpommern building, directions found here, dinner served until 10 pm). The Morning session will start at 9am at the Alfried Krupp Wissenschaftskolleg, Martin-Luther-Straße 14, 17489 Greifswald, close to the central old market place (Markt), directions found here. Conference dinner Thursday evening 7 pm Restaurant Goldmarie, Fischstraße 11, directions here. The workshop is organized together with Andy Thomas, IFW Dresden, Mathias Klaui, Mainz University, Tobias Kampfrath, Fritz Haber Institute Berlin, Timo Kuschel, Bielefeld University, Ilie Radu, TU Berlin and Markus Münzenberg, Ernst-Moritz-Arndt University Greifswald. We are seeing forward to welcome you here! For further information see the conference website with program and detailed information more ... Dates: 9. September Welcome and get together, 10. September - 11. September, 09:00 - 18:00 Uhr Location: Alfried Krupp Wissenschaftskolleg Greifswald
Heat induced frequency modulation
New publication out: A scenario for spin wave traps formed by ultrashort laser pulses
Spin waves can be controlled in local temperature gradients by femtosecond laser pulses on the micrometer length scale: in a heated region spin-waves have to adapt the local frequency in the heated region.
Read the article at Scientific Reports: Original Publication, A scenario for magnonic spin-wave traps F. Busse et al., Scientific Reports 5, 12824 (2015).
Collaboration kick-off FemtomagTopo with Charles University Prague and joint-publication with ZIK HIKE
In the framework of the Project start DAAD-PPP project with the Czech Republic in a joint project FemtomagTopo with Dr. Eva Schmoranzerova (Laboratory of Opto-Spintronics, Charles University Prague) a start-up workshop will be held on ultrafast spin dynamics in topological insulators, Thursday 12.03.
Work that is carried out together with the center of ZIK-HIKE (Centre for Innovation Competence - Humoral Immune Reactions in Cardiovascular Diseases) in the group of Dr. Mihaela Delcea , by Dr. Raghav Palankar and exchange student Tania Patin from Universitat Autònoma de Barcelona at ZIK-HIKE - on the possibilities of femtosecond lasers for targeted nanoscale manipulation, using functionalized gold nanoparticles in biological systems, has been published in Nanoscale as advance article. In joint-work with former ZIK-HIKE new directions on nanostructuring at the campus are currently developed more...
Spins, Waves and Interaction. Workshop 11.-12. September, Greifswald
The "Spins, Waves and Interaction" workshop in September, organized together with Andy Thomas, Bielefeld University, will start with a dinner Wednesday and informal meeting at evening at around 7pm at the[Fritz], Markt 13, 17489 Greifswald. The Morning session will start at 9am at the Alfred Krupp Wissenschaftskolleg, Martin-Luther-Straße 14, 17489 Greifswald. Both is close to the central old market place (Markt).
We are seeing forward to welcome you here!
Read the press information (German) more ...
DFG grants project in the Priority Program "Spin Caloric Transport" 1538
Spin polarized currents in magnetic nanostructures arising from thermal gradients? Within the second term of the Priority Programme "Spin Caloric Transport" 1538 we aim to understand thermocurrents and voltages including the spin. Together with Andy Thomas (U Bielefeld) and Christian Heiliger (U Giessen) we investigate the effects of thermal currents in magnetic tunnel junctions, and the ability to switch infomation by thermal gradients on ultrafast time scales. The research of the three collaborating groups is funded with more than 0.5 million Euro.
Read the press information (German) more ...
The new optics and cleanroom labs at Greifswald have been opened
New papers out on Arxiv
Joint work with Bielefeld-Gießen "On/off switching of bit readout in bias-enhanced tunnel magneto-Seebeck effect" and with Michael Seibt's group at Göttingen "Controlling boron redistribution in CoFeB/MgO magnetic tunnel junctions during annealing by variation of cap layer materials and MgO deposition methods"
Seminar in summer term 2014
Please check out our seminar talks announcements together with theory, Monday's 16:00 (s.t.)
Link to the Program:
Millenium Prize for Stuart Parkin
British scientist Prof Stuart Parkin, Max-Planck-Institute Halle, Germany, has won the 2014 Millennium technology prize worth €1m for research that has led to a phenomenal increase in the storage capacity of digital devices and heralded the era of cloud computing. The 2014 Millennium technology prize worth €1m will be awarded for research that has led to a phenomenal increase in the storage capacity of digital devices and heralded the era of cloud computing.
New article out!
New article out on ultrafast dynamics of FePt in Scientific Reports. In a joint work with a theory team at Madrid and HGST/ Western Digital San Jose we uncovered the ultrafast hard disc drive dynamics.
Resolving the role of femtosecond heated electrons in ultrafast spin dynamics, J. Mendil, P. Nieves, O. Chubykalo-Fesenko, J. Walowski, T. Santos, S. Pisana & M. Münzenberg, Scientific Reports 4, 3980 (2014)
Bob Meservey, the pioneer of spinelectronics, died at age of 92
The far sighted pioneer of spinelectronics, Bob Meservey, discovered electron spin-polarized tunneling in 1970, with Paul Tedrow at MIT, and demonstrated for the first time that electron spin could carry information in an electrical current. He developed the Meservey-Tedrow method to measure the spin polarization of a metal. It is a sad news that Bob Meservey died at age of 92 on June 18th in Cambridge, Mass..
Read the obituary on the MIT web page more ...
New grant for investigation of spin dynamics in topological insulators
Within the priority program SPP 1666 „Topological Isolators: Materials – Fundamentals - Applications“, we will be involved in the investigation of ultrafast spin currents generated in tolopogical insulators, in a joint project together with Dr. Tobias Kampfrath, Fritz-Haber-Institute and Prof. Christian Heiliger, University of Gießen. Start is 1th of July
Read the press release (in German) more ...
India exchange got covered in "Uni|inform"
As a starter for the new round of exchanging students with IISER Kolkata within the G-KOSS initiative between physics and chemistry, an article in the university magazine “Uni|inform” covers the last exchange with an interview, “Monkeys at the breakfast table” on page four. Link to the magazine (in German):
Uni|inform July 2013 more ...
Future of information storage – with Ranga Yogeshwar at the Ideen Expo Hannover
Come and see us at the IdeenExpo 2013 on the topic of future of information technology and energy storage. We present some new ideas in an interview with Ranga Yogeshwar at Hannover on Sunday 25th of August.
IdeenExpo 2013 more ...
Offer from University of Greifswald
The group may be moving – Prof. Markus Münzenberg got an offer for a W3 chair position at the traditional Ernst-Moritz-Arndt University of Greifswald at the baltic sea, third oldest university in Germany, since 1456. We look forward to an excellent, vibrant environment for our future research of the femto-spin and spin transport group.
Ernst-Moritz-Arndt University more ...
DFG funds a new SFB on energy conversion in materials
The German funding agency Deutsche Forschungsgemeinschaft (DFG) granted the Collaborative Research Center (Sonderforschungsbereich (SFB)) "Control of energy conversion on atomics scales". The SFB involves 17 scientific projects and an integrated graduate school. The fundig includes a sum of 8.3 Million Euro for four years. 27 researchers of the faculty of physics, chemistry and Max Plack Institute for bio-physical chemistry belong to the SFB. We contribute two projects in the context of ultrafast dynamics, "A02 Understanding and manipulating relaxation channels to tailor energy transport" and "B01 Photon-induced structural phase transition controlled by electronic correlations". Start is 1th of October.
Read the press release more ...
New paper out in Nature Nanotechnology: THz spintronics
A recent work in Nature Nanotechnology shows that ultrafast spin currents can be generated by femtosecond laser excitation. The spin current can be converted to a charge current via the Inverse Spin Hall effect (ISHE) and detected by the emission of THz radiation. The latter acts as an ultrafast Ohm-meter that allows detecting current on picoseconds time scales. The spin current can be controlled by adjacent materials (Au or Ru) and opens up possibilities for a THz spinelectronics. Vice versa this allows designing new sources of THz radiation.
Terahertz spin current pulses controlled by magnetic heterostructures
T. Kampfrath et al., Nature Nanotechnology, advance online (2013).
Read the press release of the Georg-August-University more ...
See also the press release:
Fritz-Haber Institute (FHI), Berlinmore ...
Organic molecular level spin memory works at room temperature
Approaches to store spin information on a single molecule so far involved the use of a magnetic atom. By taking a small number of non-magnetic carbon atoms, connected in three benzene rings, a material similar to graphene is realized in a tunnel junction using a chemical spin injector. This collaboration involved resreachers at IISER Kolkata, MIT, Forschungszentrum Jülich, the physics and chemistry department at Göttingen University. The results of this research have been published in the current issue of the renowned journal Nature.
Interface-engineered templates for molecular spin memory devices, K. V. Raman, et al., Nature 493, 509 (2013).
The Göttingen Spindynamics and Spintransport group wishes a Happy New Year 2013!
Last year we have started our funded research on Magnonics “Materials and Devices” which had been granted by the DFG - the interest in this young field is still increasing, visible in the recent book “Magnonics: From Fundamentals to Applications (Topics in Applied Physics) Sergej O. Demokritov (Editor), Andrei N. Slavin (Editor)”.
Also in 2012 we had the University 275 Years Jubilee with Exhibition of the University Collections, “Highlights of Physics” for young researchers and a the international conference “Universität der Dinge" in October.
Our collaboration with international groups at IISER Kolkata (G-KOSS) and MIT is prospering and we are looking into an exciting year. We wish our colleagues healthy and a Happy New Year 2013!
Read our new article on ultrafast spin dynamics
How do microscopic processes contribute to the ultrafast demagnetization using ultrafast laser pulses and how can we design materials to control the flow of hot spins? Read our article on Physical Review X (open access):
Insights into ultrafast demagnetization in pseudo-gap half metals
A. Mann, J. Walowski, M. Münzenberg, S. Maat, M. J. Carey, J. R. Childress, C. Mewes, D. Ebke, V. Drewello, G. Reiss, A. Thomas, Phys. Rev. X 2, 041008 (2012)
SPP SpinCaT PhD student workshop in Göttingen
The PhD students meeting of the DFG priority program "Spin Caloric Transport"1538 will be held in Göttingen: Monday 08.10.-Tuesday 09.10., starting 9:15, seminar room in C.02, physics building at the North Campus. It is aimed to strengthen interaction and discussion: we are seeing forward to see you here!
DFG magnonics grant for spin-wave computing
We have been awarded with a grant on spin-wave computing using magnonic structures from the German Research Foundation (DFG). Focus are novel magnonic materials and devices. Magnonic computing schemes use spin-waves for data transmission and logic operations. We will investigate the fundamental elements for that novel concept and test first simple devices: magnonic wave guides and active spin-wave elements. Spin-wave pumping and detection is realized optically using femtosecond laser pulses. The research is funded with a quater million Euro.
A successful year has ended,
with the discovery and first publication of the large magnetic thermopower in magnetic tunnel junctions,"Magneto-Seebeck effect in magnetic tunnel junctions", together with our colleagues at Bielefeld and Gießen, explored at the same time at Braunschweig and AIST Tsukuba, Japan, and Nancy, France, opening many new possibilities and research opportunities from thermal spin injection, a magnetic control of energy flow towards new logic devices.
To the more and more interest gaining field of magnonics, we have contributed summarizing activities in an extensive review "The building blocks of magnonics" and a review on tunneling "Tunneling path toward spintronics".
Our student exchange with IISER Kolkata has been started for the first round successfully found great response of the participating students.
The physics museum Physicalisches Cabinet displaying the institutes heritage from Lichtenberg to Gauß and Weber has been opened to public and objects are displayed in new light. For the 275th year celebration of our university in 2012 the article "Witnesses of the Past, Teachers of the Future? How Early Physics Instruments Helped Us Understand the World" in the December issue Collections – Wisdom, Insight, Innovation is published in the university's science magazine Georgia Augusta. Maybe an inspiring and entertaining journey into the past …
Last but not least, the DFG priority programme "Spin Caloric Transport" 1538 had been granted, see you at the first meeting 3 Kings Meeting at Bad Honnef in the new year.
We wish all the best for the upcoming year 2012!
Magnonic review published at Physics Reports
The building blocks of magnonics
B. Lenk, H. Ulrichs, F. Garbs, M. Münzenberg, Physics Reports 507, 107 (2011). The article gives a broad overview over the fast moving field, from spin-wave computing, towards introduction into band structure calculation, to methods and overview on experimental results, here with a certain focus on photo magnonics.
New effect found and published in Nature Materials
The new effect allows to switch Seebeck voltages in magnetic tunnel junction via the magnetization and allows new control to convert heat in nanostructured devices. This magneto-Seebeck effect is a new effect in the novel field of spincaloritrincs, the electronics of heat and spins.
M. Walter, J. Walowski, V. Zbarsky, M. Münzenberg, M. Schäfers, D. Ebke, G. Reiss, A. Thomas, P. Peretzki, M. Seibt, J.S. Moodera, M. Czerner, M. Bachmann, C. Heiliger, Seebeck effect in magnetic tunnel junctions, Nature Materials, advance online (2011)
Press release: German/English
DFG grants Priority Programme "Spin Caloric Transport" 1538
Spin polarized currents in magnetic nanostructures arising from thermal gradients? The new Priority Programme "Spin Caloric Transport" 1538 started in July aims to understand thermocurrents and voltages including the spin. Together with Andy Thomas (U Bielefeld) and Christian Heiliger (U Giessen) we investigate the effects of thermal currents in magnetic tunnel junctions. The research at the three universities is funded with more than a million Euro.
Review on magnonics advance online
Our review building block of magnonics with special focus on photo-magnonics appeared as "advance online" publication at Physics Reports more ....
Welcome of first guests from IISER Kolkata for collaboration and exchange
The first five students together with Prof. Swadhin Mandal and Prof. Arindam Mukherjee from IISER Kolkata have arrived to work for a two month partner project in participating groups to establish G-KOSS in chemistry and physics on spin transport in organic materials, ultrafast spin dynamics, correlation in molecular magnets and molecular synthesis. Welcome!
Saturday morning physics and lecture series on the history of physics
14. Mai 2011, 11 Uhr c.t., Faculty of Physics, Max-Born-Hörsaal
Prof. Dr. Markus Münzenberg »Vom chinesischen Südweiser zum Musiktape bis zur Harddisk: 3000 Jahre Magnetismus (From south pointing chariot, tape to hard disc drive: 3000 years of magnetism)« Announcement, Flyer
Lecture series on the history of physics:
This summer term a lecture series is given - organized by students - covering the fields in-between physics, mathematics, philosophy and history - historic instruments, biographies or groundbreaking developments. The lecture series is open for all interested students the general public.
History of physics: 18 Uhr c.t., Faculty of Physics, Max-Born-Hörsaal
Göttingen University helps partner Universities in Japan
Georg-August.Universität Göttingen Japanhilfe Over the past two weeks, the “Göttingen region’s direct aid for Japan” aid programme has collected almost € 57,000 in donations. The money will go directly to help Japanese students and young researchers and scholars affected by the disaster.
Discussion on possibilities and riscs of nano technology:
Discussion on possibilities and risks of nano technology, CinemaxX 14.04.,17:30. Official link:Bürger treffen Experten, Nano heute, morgen und übermorgen
Nanotechnology has the potential to solve challenges we are facing today in economical use of energy, resources or in medicine - it is utilized in IT products miniaturization and by nature itself. Generally exposition arises only from free nanoparticels. However what are potential risks of a "wrong" use of it? Nanoparticles are already found in many consumer products -textiles (nanosilver), cosmetics (sun protection) or food-. Aim of this discussion is to inform and to discuss actions to be taken for consumer protection which is a paramount prerequisite of responsible science. This dialog is initiated by the ministry of education and research (BMBF) with the following speakers:
“Nano – Was ist das und was kann daraus werden?“
Markus Münzenberg, Georg‐August‐Universität Göttingen
“Nanotechnologie heute, morgen und übermorgen“
Rolf Buschmann, Verbraucherzentrale Düsseldorf, Steffi Friedrichs, Nanotechnology Industry Association, Brüssel, Katja Nau, KIT – Karlsruher Institut für Technologie
For more background see nanopartikel.info, Wikipedia on nanotoxology and actual article in the Physik Journal on Nanoparticle Cell interaction resolved by optical microscopy beyond the resolution limit.
Read the review article with G. Miao and J.S. Moodera
The article on current developments in the field of spintransport is now online in Reports on Progress in Physics. Title: "Tunneling path toward spintronics".
Review article "Building Blocks of Magnonics" on photo-magnonics on arXiv
Following a suggestion after the APS magnonics symposium in Portland 2010, we have now compiled recent ideas in this young field. The review article "Building blocks of magnonics" by Benjamin Lenk, Henning Ulrichs, Fabian Garbs and Markus Münzenberg can be read as a preprint. In focus is the control of localization and delocalization on the formation of bands in a magnonic crystal and the ultrafast laser excitation of spin waves (photo-magnonics).
Round table gave planned IRTG a name
The collaboration with IISER Kolkata is further progressing: the intensive one week meeting with 10 researchers from IISER Kolkata in December tightened the research foci and formed new interactions. And, it gave the project a name: G-KOSS (Göttingen-Kolkata school on Open Shell Systems). In addition we are very happy that Prof. Herbert W. Roesky, who has a longstanding tradition of contacts to Indian researchers, agreed to be "senior advisor" for the school.
Article on photo-magnonics published at Applied Physics Letters
Our work on structured CoFeB films, with very low intrinsic damping, appeared in the first September issue of Applied Physics Letters:
Magnonic spin-wave modes in CoFeB antidot lattices, Appl. Phys. Lett. 97, 092506 (2010).
We show that we can excite spin-wave Bloch modes at the zone boundary in the magnonic crystal with high intensity if these are energetically degenerated. Key is a low filling fraction to observe these modes.
The organization for the International and Interdisciplinary Research Training Group with IISER Kolkata is rapidly progressing: Prof. Sushanta Dattagupta, Director of IISER Kolkata, will visit Göttingen 11th to 13th of October. A round table will take place at Göttingen December 13th to 18th for the detailed planning of the subgroups and to forster collaborations further. Please look for the program and informations that I will put on a Research Training Group web-site.
Photo-magnonics: New articles on the preprint server related to magnonics and photo-excitation of spin waves
Tuning spin-wave states in magnonic crystals from localization to free spin-wave states: Magnonic spin-wave modes in CoFeB antidot lattices, arXiv:1006.4038
spin-wave interaction in Ni films:Unusual spin-wave population in nickel after femtosecond laser pulse excitation,arXiv:0803.3686
and on the detection sensitivity by optical methods:
Analytical expression of the magneto-optical Kerr effect and Brillouin light scattering intensity arising from dynamic magnetization with Jaroslav Hamrle and collaborators, arXiv:1006.1906
Read the articles Physics Viewpoint "Taking advantage of nature for a greener nonvolatile memory" by Markus Münzenberg and Jagadeesh S. Moodera, Physics 3, 19 (2010)
and News and Views in Nature Materials "Magnetization dynamics: Ferromagnets stirred up" by Markus Münzenberg, Nature Materials 9, 184 (2010)
Former colleague from MIT Dr. Tiffany Santos, now at Argonne National Laboratory wins prestigious L'Oreal Award 2009 . "The aim of my research is to understand how materials interact with each other when brought together at the atomic level," Santos said. "If we can understand the origin of a material's properties at the nanoscale, then we can design and create new materials for the next generation of electronic devices that meet these global challenges".
Dr. Jagadeesh Moodera wins the Oliver E. Buckley Condensed Matter Prize together with Robert Meservey, Terunobu Miyazaki and Paul Tedrow for pioneering work in the field of spin-dependent tunneling and for the application of these phenomena to the field of magnetoelectronics. In addition he was awarded by the National Science Foundation as American Competitiveness and Innovation Fellow "For his achievements and world-leading role in the field of spintronics".