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Ultrafast demagnetization through rapid spin-wave generation

Excitation of a ferromagnetic material with a femtosecond laser pulse causes an ultrafast magnetization drop, but the deeper mechanism behind this ultrafast drop has been disputed for many years. Physicists within the CRC/TRR 227 now show that ultrafast generation of non-thermal spin waves can explain a rapid magnetization loss within 200 femtoseconds (fs) consistent with experiments.

Feb 12, 2024

TRR227 hosts Ultrafast Magnetism Conference 2024

TRR227 PIs Martin Weinelt and Stefan Eisebitt serve as Conference Chairs of the Ultrafast Magnetism Conference 2024 , being held at the Henry Ford Building of FU Berlin, 2 - 6 Sept. 2024.

Dec 23, 2023

Dr. Lisa-Marie Kern - Carl Ramsauer Prize 2023 of the Physikalische Gesellschaft zu Berlin

For her outstanding dissertation, Lisa-Marie Kern, a former iRTG member of our TRR 227, was awarded with the Carl-Raumsauer-Preis 2023 of the Physikalische Gesellschaft zu Berlin. - Congratulations!

Nov 22, 2023

Max Born Prize and Medal 2024 for Ingrid Mertig (MLU Halle-Wittenberg)

The Deutsche Physikalische Gesellschaft (DPG) and the Insitute of Physics (IOP) announced the awardee of the Max Born Prize and Medal for the year 2024.

Nov 16, 2023

New B11 project led by Hélène Seiler - Supplementary proposal approved

Hélène Seiler, tenure track W1-W2 professor at the Physics Department of FU Berlin, proposed a new project entitled "Probing exciton structure and dynamics in two-dimensional magnets and spintronic heterostructures". DFG now approved this supplementary project as B11 within our CRC/TRR 227. Funding is granted for year 3 and 4 of the 2 nd funding period and starts January 1, 2024.

Nov 01, 2023

Electrical measurements at picosecond timescale - New TRR 227 paper published in Nano Letters

Latest TRR 227 results of projects B07 and B08 on probing the formation of dark interlayer excitons via ultrafast photocurrent just appeared in the journal Nano Letters of the American Chemical Society

Oct 20, 2023

Terahertz currents launch massive spin rotation in an antiferromagnet - TRR 227 results published in Nature Communications

Researchers of the TRR227 at FU Berlin (projects A05 and B02 of PI Tobias Kampfrath) with collaborators in Mainz and Dresden find that spin dynamics in an antiferromagnetic metal can be excited by terahertz electric rather than magnetic fields. Enhanced by exchange-interaction, the spins are deflected by as much as 30° out of their equilibrium direction. By demonstrating this highly nonlinear response, spin rotation by 90° and, thus, ultrafast writing of an antiferromagnetic bit by terahertz electric currents comes into close reach.

Sep 29, 2023

Orbital currents can go far – TRR 227 results published in Nature Nanotechnology

TRR 227 PI Tom S. Seifert (project A05) and colleagues published their latest work on ultrafast orbital currents in the journal “Nature Nanotechnology”. Using terahertz-emission spectroscopy, the researchers found strong evidence for optically triggered orbital angular momentum currents in Ni|W thin-film stacks. Surprisingly, those currents seem to travel for 10s of nm without undergoing any scattering.

Aug 28, 2023

TRR 227 project leader Dr. Sangeeta Sharma has been appointed as professor in the field of "Theoretical Solid State Physics"

We are delighted to announce that on June 26, 2023, Dr. Sangeeta Sharma has been installed as a professor at FU Berlin, in a joint appointment with the Max Born Institute.

Jul 10, 2023

TRR227 postdoc Dr. Bo Liu obtains new position

Dr. Bo Liu, who worked as a postdoc in project A01 of Martin Weinelt for 3 years from 2019 until 2022, accepted a tenure-track assistant professorship at Nanjing University , China.

May 24, 2023

Insights to spin transport–driven ultrafast magnetization dynamics - TRR 227 results published in Science Advances

TRR 227 PI Martin Weinelt (project A01) and coworkers published their latest work on ultrafast magnetization dynamics in the journal "Science Advances". Using time- and spin-resolved photoemission spectroscopy, the researchers studied an antiferromagnetically coupled Gd/Fe bilayer, a prototype system for all-optical switching. Spin transport leads to an ultrafast drop of the spin polarization at the Gd surface, demonstrating angular-momentum transfer over several nanometers.

May 23, 2023

2023 Terahertz Science and Technology Roadmap just published in the Journal of Physics D: Applied Physics

The Journal of Physics D: Applied Physics just published “ The 2023 Terahertz Science and Technology Roadmap ”. It contains two contributions from the Collaborative Research Center TRR 227 “Ultrafast spin dynamics” and the Terahertz Physics Group fo the FU Physics Department: a perspective article on “Terahertz spintronics and magnetism” and another one on “Terahertz emission spectroscopy and imaging”.

Apr 27, 2023

Editors' suggestions of Phys. Rev. journals highlight TRR 227 research on THz spintronics

Understanding and improving spintronic terahertz-wave emission: Spintronic terahertz (THz) emitters (STEs) are a novel class of broadband, low-cost and efficient THz sources (see Fig. 1). They exhibit interesting opportunities for applications in the fields of THz physics and THz photonics where THz electromagnetic pulses are used for material characterization, imaging and spectroscopy. Consequently, STEs are meanwhile commercially available from the Berlin-based startup TeraSpinTec GmbH .

Mar 14, 2023

Dr. Maximilian Paleschke - Heinz-Bethge Prize for Material Sciences 2022

For his excellent dissertation, Maximilian Paleschke was awarded with the Heinz-Bethge-Prize for Material Sciences 2022. - Congratulations!

Jan 18, 2023

Stuart Parkin - one of the Highly Cited Researchers 2022

In this year’s survey of Clarivate™ "Highly Cited Researchers" , almost 7.000 researchers are listed across all disciplines of science, 369 of them work in Germany. Stuart Parkin of the MPI für Mikrostrukturphysik in Halle and TRR 227 PI of project B10 is one of them. - Congratulations!

Nov 28, 2022

Crowded auditorium at the PhD Focus Session 2022

This year’s PhD Focus Session of the division MA at the DPG Meeting of the section condensed matter (SKM), held at the University of Regensburg, was jointly organized by PhD students from the collaborative research centers TRR227 “Ultrafast Spin Dynamics” from Berlin/Halle and TRR173 “Spin+X” from Mainz/Kaiserslautern.

Oct 05, 2022

TRR 227 results in Nature Communications - Physicists generate new nanoscale spin waves

Strong alternating magnetic fields can be used to generate a new type of spin wave that was previously just theoretically predicted. This was achieved for the first time by a team of physicists from Martin-Luther-Universität Halle-Wittenberg (MLU). They report on their work in the scientific journal “Nature Communications” and provide the first microscopic images of these spin waves.

Sep 15, 2022

TRR227 scientist Dr. Unai Atxitia accepted new position

Dr. Unai Atxitia, PI of project A08 during the 1 st funding period, accepted a tenure-track position as research scientist and team leader at the Instituto de Ciencia de Materiales de Madrid , Spain.

Aug 01, 2022

Single-pulse switching in ferrimagnets - TRR 227 paper in Phys. Rev. Lett.

U. Atxitia (project A08) and his PhD student F. Jakobs recently published a paper on universal criteria for single femtosecond pulse ultrafast magnetization switching in ferrimagnets in Physical Review Letters.

Jul 12, 2022

TRR 227 spintronics paper published in Nano Letters

An intermediate layer consisting of a few atoms helps to improve the transport of spin currents from one material to another. Until now, this process involves significant losses.

May 10, 2022