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2024-02-07: Ausschreibung Doktorand*innen oder PostDoc Stelle
Wir haben die Stelle eines wissenschaftlichen Mitarbeitenden TVL 13 ausgeschrieben: https://www.uni-due.de/karriere/stelle.php?kennziffer=086-24 . Es können sich sowohl Personen, die an einer Promotion interessiert sind, als auch promovierte Personen bewerben, die entweder Ihr eigenes Projekt mitbringen und dieses durch eine(n) weiteren Mitarbeiter*in verstärken wollen, oder selber die PostDoc Position annehmen wollen. Die PostDoc Stelle könnte nach zwei Jahren nach positiver Evaluation um weitere zwei Jahre verlängert werden.
2024-02-02: We welcome Emmanouil Kasotakis to our team!
He will work on his PhD thesis within the DFG project titled "Tailoring magnetism of High Entropy Alloys (HEA) by high energy ball milling".
His research will be focused on the development of innovative (soft or hard) magnetic HEA materials with chemical and mechanical robustness.
We wish him success in his research and excellent results!
2024-01-18: "Cellular precipitation in Ni-Mn-Sn revealed", Phys. Rev. Materials 7 (2023) 124411
"Cellular precipitation in Ni-Mn-Sn revealed", Phys. Rev. Materials 7 (2023) 124411 Combining the expertise of 5 participating projects in the SFB/TRR 270 HoMMage the location and morphology of ferromagnetic precipitates in Ni-Mn-Sn was determined. Ni50Mn45Sn05 heated above 600 K decomposes into ferromagnetic Ni2MnSn precipitates in an antiferromagnetic NiMn matrix. If an external magnetic field is applied during annealing, magnetic hysteresis curves with high coercive fields of up to 5 T can be achieved. The origin of this hysteresis has been attributed to the coupling of the antiferromagnetic matrix L10 NiMn with ferromagnetic precipitates (Sn enriched regions), whose location and morphology were not known. To close this knowledge gap, a range of sophisticated experimental techniques – ranging from magnetic force microscopy over transmission electron microscopy to atom probe tomography -was applied aside from conventional magnetometry and x-ray diffraction. The decomposition type is identified as a cellular precipitation starting at grain boundaries and growing into the grains. This leads to a multilayer thin film like lamellar structure with a lamella thickness in the nm range as seen in the attached figure. These results may provide a basis for understanding the magnetic interactions, which lead to the magnetic hysteresis with ultra high coercivity in these types of "shell ferromagnets"

Abb: a) HAADF STEM image of the sample annealed for 24 h at 700 K. The decomposition product of phase I toward Ni2MnSn and NiMn is visible and forms a lamellar structure.
(b) HAADF STEM image of the region marked in (a) (yellow rectangle). The thickness of the Ni2MnSn lamellar precipitates is around 10 nm.
(c) EDX mappings of Ni, Mn, and Sn performed on the area shown in (b).
(d) EDX linescans measured within the yellow rectangles shown in (b). The x-axes of the plots of the linescans follow the yellow arrows.
2023-08-17: GRATULATION: MSc. Nanoeng. Inci Nur Sahin

Die Abbildung zeigt die chemische Zusammensetzung eines typischen Partikels.
Wir freuen uns mit Inci über den Abschluss Ihrer Masterarbeit im Studiengang Nanoengineering. Ihre Arbeit und ihr Abschlusskolloquium wurden mit den jeweils bestmöglichen Noten bewertet. Ihre Forschung zu "Optimierter Hyperthermie Ansatz mittels Fe3O4/SiO2/Ni Multischalen Nanoellipsoiden" demonstriert eine neues Konzept zur biomedizinischen Theranostik mit synthetischen Antiferromagneten, die aus Magnetit Halbschalen in einer Siliziumdioxid Hülle bestehen, naßchemisch herstellbar und hoch-skalierbar sind, sowie ohne magnetische Streufelder in biomedizinischen Anwendungen verwendet werden könnten.
Die Arbeit ist hier zu finden.
2023-08-12: Pinned magnetic moments in the collinear antiferromagnet PdMn
Pinned magnetic moments in the collinear antiferromagnet PdMn In a joint research work within the CRC/TRR270 "Hysteresis design of magnetic materials for efficient energy conversion" Nicolas Josten (PhD candidate) in project A04 could show that annealing the collinear antiferromagnet PdMn with excess Pd in a magnetic field produces strongly pinned magnetic moments in the annealing field direction. This behavior can be understood with the help of the magnetic-field-biased diffusion model. Here, the magnetic field creates an energy difference between the two possible occupations of the antiferromagnetic Mn-sublattices by the Pd-excess atoms. This, mediated by diffusion, leads to an imbalance in the amount of the Pd-excess atoms in these sublattices and, subsequently, to an imbalance in the total magnetization of the sublattices. For Details see: Annealing time, temperature, and field dependence of pinned magnetic moments in the collinear antiferromagnet PdMn
2023-08-09: Helical magnetic structure of epitaxial films of nano-laminated Mn2GaC MAX phase
In a multinational collaboration we could identify a complex magnetic arrangement of Mn magnetic moments, that is a helical magnetic structure consisting of the ferromagnetically coupled Mn-C-Mn slabs that are twisted across the Ga layer by 167.2 deg with respect to the next Mn-C-Mn slab. As a result, the magnetic structure presents a spiral propagating along the out-of-plane direction (hexagonal c axis) with a pitch of around 14 lattice constants. For Details see: Annealing time, temperature, and field dependence of pinned magnetic moments in the collinear antiferromagnet PdMn
2023-08-01: Bachelor Thesis: Magnetic Resonance Spectroscopy of (Fe,Mn,Ni)PS3 van der Waals single crystals
Wir begrüßen Moritz Küster in unserem Team. Er forscht seit Juli im Rahmen seine Bachelorarbeit am Verständnis der magnetischen Wechselwirkungen in quasi-2D van der Waals Materialien. Mittels Elektronenspinresonanz als Funktion von Temperatur und Winkel versucht er die intrinsischen magnetischen Phasenübergänge zu identifizieren. Die ersten überraschenden Ergebnisse liegen vor.
2023-09-07: WIR GRATULIEREN !
Nicolas Josten ist am 22.07.2023 kirchlich getraut worden.
Wir freuen uns mit Ihm und seiner Frau und wünschen beiden alles Gute !
2023-07-18: Femtosecond Laser Ablation-Induced Magnetic Phase Transformations in FeRh
In a trilateral French-Spanish-German collaboration we investigated the ablation properties of FeRh films. We found that the initial FeRh film displayed a reversible antiferromagnet-ferromagnet phase transition and the laser-ablated structures exhibited irreversible changes in their magnetic properties. Fluence-resolved measurements clearly demonstrate that the ablation threshold coincides with the threshold of the antiferromagnet-to-ferromagnet phase transition. For details see: Femtosecond Laser Ablation-Induced Magnetic Phase Transformations in FeRh Thin Films .
2023-07-18: Easy up-scalable synthesis for ferrite nanoparticles
In a joint transatlantic effort we analyzed the magnetic and structural character of ferrite nanoparticles. The results are astonishing. For more information , please see One pot, scalable synthesis of hydroxide derived ferrite magnetic nanoparticles .
2023-08-18: Impressionen der erfolgreichen Begehung zur 2. Förderperiode des SFB/TRR270
Hier geht es zur Website.
2023-06-29: Ni-Mn-Sn Heusler alloys manufactured by e-beam and laser powder bed fusion
In a recent joint publication of the CRC/TRR270 we published a comparative study of additive manufacture Ni-Mn-Sn Heusler alloys.
Using an uncommon PBF-EB/M spot melting strategy, for the first time, crack-free Ni-Mn-Sn bulk material were produced and the chemical, microstructural, and magnetic properties were analyzed. Results on the magnetocaloric effect of the consolidated samples are reported. For details see S.-K. Rittinghaus et al. , Additive Manufacturing Letters 7 (2023) 100159 .
2023-06-16: Good Bye Manolis!
After his 5-months ERASMUS-funded internship Emmanouil Kasotakis left us after setting up and testing a now fully functioning sputter deposition system which he commissioned together with Moritz Vanselow and Dr. Anna Semisalova.
We wish him a fruitful and successful career wherever his interest my lead him.
2023-06-13: Towards THz Physics with GHz excitation (inertia in spin dynamics)
The dynamics of magnetic moments consists of a precession around the magnetic field direction and a relaxation towards the field to minimize the energy. While the magnetic moment and the angular momentum are conventionally assumed to be parallel to each other, at ultrafast time scales their directions become separated due to inertial effects. The inertial dynamics gives rise to additional high-frequency modes in the excitation spectrum of magnetic materials. Here, our international collaboration reviews the recent theoretical and experimental advances in this emerging topic and discuss the open challenges and opportunities in the detection and the potential applications of inertial spin dynamics.
For further details see https://doi.org/10.1016/j.jmmm.2023.170830.
2023-05-02: We welcome Berna Gündogdu Gültepe!
She completed her master degree at Istanbul University and is now a visiting researcher at the AG Farle team to develop a project until 31 October 2023.
Focusing on Heusler alloys, the project includes the preparation and examination of multilayer thin films prepared by flash evaporation of multi-element materials.
2023-04-14: Welcome to Elisavet Papadopoulou
We welcome Elisavet Papadopoulou to our team, who will work on her Master thesis in NanoEngineering. With the help of Dr. Natalia Shkodich, she will focus on the synthesis of novel room temperature CoMnFeNiIn high entropy alloys by High energy ball milling and study their structural, chemical and magnetic properties.
We wish a success in her research and excellent results!
2023-03-30: We welcome Emmanouil Kasotakis (Aristotle University of Thessaloniki) to our team
Within his 5-months ERASMUS-funded internship Emmanouil will learn the basics of vacuum techniques and magnetron sputtering. He will work on deposition of Fe-based ferromagnetic alloys for magnetocaloric and permanent magnet applications. We wish him fruitful and successful stay in our team!
2023-03-29: New publication in "Nano-Structures & Nano-Objects": https://authors.elsevier.com/c/1goto,rVMJnm~Z2444
In our trilateral Armenian, German, Greek project "MaNaCa" we discovered an interesting magnetic composite:Carbon-encapsulated iron-cementite (Fe/Fe3C) magnetic nanoparticles were synthesized by an upscalable solid-state pyrolysis method using iron phthalocyanine as a precursor. The dependence of the structure, morphology and magnetic properties on the pyrolysis conditions is presented. Thenanocomposite contains nanoparticles made of cementite with a small fraction of iron, with an averagediameter of 15 nm embedded in an amorphous carbon matrix.A 3 nm thick graphite shell is formed on the surface of the particles. The volume fraction of α-Feincreases almost linearly on increasing pyrolysis temperature: from 0.5% for the sample synthesizedat 800°C up to 11% for a 900°C pyrolysis temperature, resulting in an increase of the saturationmagnetization from 14.0 to 17.74 Am2/kg and a decrease of the coercivity from 49.34 to 10.74 kA/m
2022-11-07: We welcome Aydan Akyildiz from Gebze Technical University (Turkey)
Aydan will work on her master thesis in our group till February 28, 2023. She studied Physics Engineering at Istanbul Technical University. Her Master thesis will be centered around the magnetic, morphological and structural characterization of Cementite nanoparticles.
2022-10-16: New Publication on a high entropy alloy soft magnet
Soft magnets - that is magnets with a low coercivity - find many applications in sensorics and automobile industry for example. Here a mechanical and environmental robustness is of extreme importance - properties which high entropy alloys provide. Magnetism in such alloys has become a major focus of research in HEAs. In our recent publication we show how to tune magnetic properties in nanocrystalline CoCrFeNiGax (x = 0.5, 1.0) High Entropy Alloys by mechanical treatment.
2022-08-26: New Publication of effects of inertia in the precession of the magnetization
High-frequency (THz) excitation of magnetization precession is considered as a new promising route for low energy and ultrafast information processing in next-generation devices. These concepts based on magnon propagation are based on conservative concepts taking the Landau-Lifschitz- Equation into account. In our publication we show that conventional GHz precession of long wavelength magnons is accompanied by additional higher frequency excitations approaching the THz range. This effect is based on the re-discovery that inertia effects in magnetization dynamics are present.
2022-06-20: "MaNaCa": highlighted by video on YOU Tube
Unser EU Project "MaNaCa": Magnetic Nanohybrids for Cancer Therapy is highlighted by an informational video on YOU Tube. https://youtu.be/hcDZRhRTgWg
2022-05-09: Humboldt Research Award 2022 (Prof. H. Srikanth)
From South Florida to Duisburg-Essen, AgFarle
Professor Hari Srikanth is a winner of the Humboldt Research Award 2022. As an internationally acclaimed researcher in the field of magnetism and magnetic materials and especially in nanomagnetism, he pioneered the method of radio frequency transverse susceptibility for precise measurements of magnetization dynamics. His current interests focus on exploring novel interfaces in core-shell nanoparticles and thin film heterostructures with the goal to improve our understanding of exchange coupling, proximity effects and thermal spin transport in these systems. In Germany, Professor Srikanth will continue his experimental studies probing interface magnetism in nanostructures and heterostructures, which is of importance for the development of energy saving information processing and biomedical diagnosis and therapy.
Professor Srikanth is hosted by Professor Michael Farle at the University of Duisburg Essen.
2022-03-28: Welcome to Moritz Sünner and Moritz Vanselow
Moritz Sünner and Moritz Vanselow joined our team to work on their Bachelor Thesis in Energy Science and Physics, respectively. Moritz S. will study the correlation of microstructure and magnetic properties in high entropy alloys prepared by high energy ball milling (Project S01 in the SFB/TRR 270) , and Moritz V. will investigate magnetic resonance phenomena in Heusler compounds (Project A04 in the SFB/TRR 270) with special emphasis on identifying the intrinsic mechanisms to enhance the coercive field.
WELCOME to our team and SUCCESS to your research!
2021-11-25: Welcome to Assoc. Prof. Dr. Asli Cakir
We welcome Assoc. Prof. Dr. Asli Cakir from the Department of Metallurgy and Materials Engineering, Mugla Sitki Kocman University, Turkey, who is supported by a fellowship granted by the Scientific and Technological Research Council of Turkey and will be with us until November 2022. Dr Cakir will carry out work on the investigation of interfacial pinning phenomena in artificial shell-ferromagnets by preparing multilayer Heusler films and studying their high-coercivity properties. During a previous visit to our laboratories in 2013, she had carried out research related to the construction of structural and magnetic phase diagrams of functional Heusler materials, which also made up the main theme of her PhD studies. Since then, we have been collaborating through mutual visits on the properties of magneto-structural transitions in Heusler alloys.
We wish her a fruitful and enjoyable stay in Duisburg..
2021-11-03: We WELCOME Sakia and Jonas in our team!
B.Sc. Sakia Noorzayee und B.Sc. Jonas Wiemeler started their Master Theses (Physics) on Sept 1st, 2021 in our group.
Jonas will work with Anna Semisalova to produce ultraclean Fe/Rh films in UHV to better understand and describe the
Spin dynamics of ultrathin Fe/Rh multilayers.
And Sakia works with Nicolas Josten to improve The magnetic hysteresis of transition metal alloys through magnetic annealing exemplified by NiMn and CoTiGe.
We wish them a good time and excellent results!
2021-10-19: Genauer geht nicht!
Neuartiger Sensor detektiert Wassermoleküle bei kleinsten Konzentrationen

Wissenschaftlerinnen und Wissenschaftlern der Universität Duisburg-Essen und der Staatlichen Technischen Universität Juri Gagarin in Saratow haben einen Sensor entwickelt, der Wassermoleküle erkennt, die auf seine Oberfläche sinken. Basis des Sensors sind MXene, zweidimensionale anorganischen Verbindungen, die aus nur wenige Atome dicken Schichten von Übergangsmetallcarbiden und -nitriden bestehen.

Die relative Luftfeuchtigkeit wird zu einem wichtigen Faktor, der komfortable und sichere Umgebungsbedingungen in der biomedizinischen Verarbeitung, der Mikroelektronik und der Gesundheitsüberwachung definiert und moderne Geräte zu seiner präzisen Kontrolle erfordert. Kommerzielle Sensoren, die auf voluminösen Materialien basieren, sind jedoch nicht in der Lage, sehr niedrige H2O-Konzentrationen (< 50 ppm) zu erkennen, was den Einsatzbereich der Sensoren erheblich einschränkt.

Ein Team von Wissenschaftlern der Universität Duisburg-Essen (Deutschland) und der Staatlichen Technischen Universität Juri Gagarin in Saratow (Russland) geht dieses Problem mit einer völlig neuen Strategie an. Sie verwenden zweidimensionale nanometrische Materialien, die in der Lage sind, kleinste Mengen Wassermoleküle zu erkennen, die auf ihre Oberfläche sinken. "Auf diese Weise verbessert sich die Sensorleistung enorm - die Nachweisgrenze wird weit unter den bisherigen Stand der Technik verschoben. Mehr geht eigentlich nicht.", freut sich die Erstautorin Hanna Pazniak. Sie ist seit Oktober 2020 an der UDE und forscht eigentlich zu magnetischen MAX-Phasen im Sonderforschungsbereich/Transregio 270 - "Hysterese-Design magnetischer Materialien für effiziente Energieumwandlung" in Teilprojekt B02. Die Entwicklung des neuen Sensors ist ein gutes Beispiel dafür, wie Forschung in kurzer Zeit auf andere Gebiete übertragen werden kann.

Die Schlüsselrolle spielten MXene - eine neue Klasse von zweidimensionalen Übergangsmetallcarbiden und -nitriden. Mo2CTx MXenes werden verwendet, die ein riesiges Verhältnis von Oberfläche zu Volumen aufweisen. Die entworfenen Sensoren zeigen eine höhere Empfindlichkeit als andere MXene gegenüber H2O-Dämpfen mit einer Nachweisgrenze von 10 ppm, was der niedrigste bisher bekannte Wert ist. Eine hohe Reproduzierbarkeit und eine Langzeitstabilität für mindestens 6 Monate sind weitere Eigenschaften, die für den Serieneinsatz Voraussetzung sind.

Insgesamt versprechen die herausragenden Eigenschaften der entwickelten Mo2CTx MXene viele mögliche Anwendungen, bei denen eine exakte Hygrometrie Voraussetzung ist. Die Forschungsergebnisse wurden kürzlich in der angesehenen Fachzeitschrift Advanced Materials veröffentlicht (https://doi.org/10.1002/adma.202104878).

Weitere Informationen:
Dr. Hanna Pazniak, Fakultät für Physik, hanna.pazniak@uni-due.de
Prof. Dr. Ulf Wiedwald, Fakultät für Physik, ulf.wiedwald@uni-due.de
2021-10-07: CONGRATULATIONS: Prof. apl. Dr. Ulf Wiedwald
Wir gratulieren Ulf herzlichst zur Ernennung zum außerplanmäßigen Professor der Fakultät für Physik. Ulf hat nach einem Beginn an der TU Braunschweig, einem Zwischenstopp in Duisburg und Ulm sein wissenschaftliches Heim an unserer Fakultät und der Fakultät für Medizin seit einigen Jahren aufgebaut. Seine Arbeitsgebiete spiegeln diesen Spagat wieder. Einerseits untersucht er biomedizinische Fragestellungen, deren Beantwortung zur Entwicklung neuer Krebstherapien eingesetzt werden können, und andererseits beschreitet er neue Wege in der Herstellung sogenannter MAX-Phasen Materialien, die in den letzten Jahren ein exponentiell wachsendes Interesse aufgrund ihrer sehr speziellen Eigenschaften gefunden haben.
2021-10-01: Dr. Natalia Shkodich neu in unserem Team
Wir begrüßen Dr. Natalia Shkodich (MISIS und ISMAM, Moskau, Russland) in unserem Team.
Sie wird als Junior-Gruppenleiterin im Rahmen des CRC / TRR 270 "Hysteresis design of Magnetic Materials for efficient energy conversion" an neuen "Super-Magneten" auf Basis innovativer Werkstoffe wie "High-Entropy Alloys (HEAs)" und verwandten "Compositionally complex magnetocalorics (CoCoMaCa)" forschen. Hierzu stehen hier die neuesten Apparaturen zur Analytik auf atomarer bis makroskopischer Skala zur Verfügung. Eine der Herausforderungen ist beispielswese die Verknüpfung der viel-elementigen Materialien zu einem Produkt, welches die elektrische Valenzelektronenkonzentration - und somit Eigenschaften - von Eisen hat, ohne Fe zu enthalten. Schwerpunkt der Synthese dieser Materialien, die aus 5 und mehr Elementen zusammengesetzt sein können, wird auf einem relativ neuen Verfahren des "High Energy Ball Milling" beruhen.
Studierende, die Interesse an der Mitarbeit in einem herausfordernden Projekt haben, melden sich bitte direkt bei Frau Dr. Shkodich (natalia.shkodich@uni-due.de) oder Prof. Farle (farle@uni-due.de") .
2021-09-30: Action Call of the European Raw Materials Alliance
The activities of the collaborative research center SFB/TRR 270 of which we are a partner started ahead of its time recognizing the importance of magnet technology for a carbon-neutral future of Europe. Learn more about it here .
2021-09-09: 25. Deutsche Physikerinnentagung
Vom 8. bis 10. November 2021 konzentriert sich die 25. Deutsche Physikerinnentagung drei Tage lang auf den fachlichen Austausch sowie auf die Karriereplanung und das Networking von Frauen in der Physik.
Zur Website der DPG
2021-08-24: 2nd Int. Workshop on Functional MAX Materials
We are organizing an international workshop on the properties of Functional MAX Materials (2nd FunMAX 2021) at the Kirensky Institute of Physics and Siberian Federal University in Krasnoyarsk, September 14-17, 2021 in an ONLINE format. The 2nd FunMAX workshop will bring together scientists interested in the properties of MAX phase materials including their 2D derivatives (MXenes). Registration is free and open till Aug 30.2021. Please use this link and send it to funmax@kirensky.ru.
2021-07-14: Förderzusage: Programm zur Förderung des exzellenten wissenschaftlichen Nachwuchses
Wir gratulieren Benjamin Zingsem zur Förderung seines Projekts "Towards Magnetic Resonance Observed by Transmission electron microscopy" durch die UDE. Die Förderung in Höhe von rund 30 k erfolgt im Rahmen des Programms zur Förderung des exzellenten wissenschaftlichen Nachwuchses.
2021-06-18: Würdigung für Dr. Benjamin Zingsem (Projekt Z02 des SFB/TRR 270)
Herr Dr. Benjamin Zingsem wurde im Rahmen des Dies Akademicus 2021 der Universität Duisburg-Essen für die beste Promotion 2020/21 an der Fakultät für Physik ausgezeichnet.
https://www.youtube.com/watch?v=bMltwjPdWZA
Wir freuen uns mit ihm und auf eine weitere Zusammenarbeit.
2021-05-31: Theory predicts Magnetic Nutation Waves
In our recent publication on "Dispersion relation of nutation surface spin waves in ferromagnets" we predict the existence a new type of spin wave with surprising high frequency properties. This finding may become of importance for the development of novel magnonic information processors at THz frequencies. Contact: anna.semisalova@uni-due.de
2021-05-25: MaNaCa Training Workshop 2021
We are organizing a summer school as part of our European project with Armenia and Greece "Magnetic Nanoparticles for Cancer Therapy (MaNaCa)" (see for more details http://www.h2020-manaca.eu/). The conference will take place on June 16-18, 2021 in an online format.
2020-11-10: Neue AG Mitglieder
Wir freuen uns, Frau Kübra Yildiz Aktas und Herrn Ali Can Aktas begrüßen zu können, die im Rahmen eines Stipendiums des CRC/TRR 270 "Hommage" in den Projekten B09 und A04 an Shell ferromagnetic materials: Tuning the magnetic hysteresis by nanoscale selective phase decomposition und "Hierachical structuring of magnetocaloric materials with nanometer resolution" forschen werden.
2020-10-07: DAAD funded research stay of scientists from Russia
We welcome in our group Dr. Natalia Shkodich (Merzhanov Institute of Structural Macrokinetics and Materials Science, Russian Academy of Sciences) and Dr. Mikhail Cherkasskii (Saint Petersburg State University) who recently joined us for a 3 months research stay funded by DAAD scholarships ("Research stays for University Academics and Scientists, 2020" and "Dmitrij Mendeleev" Program).

Dr. Natalia Shkodich is an expert on combining High-Energy Ball Milling (HEBM) and Spark Plasma Sintering (SPS) to produce nanostructured and amorphous materials from immiscible metals (so-called pseudo alloys), metallic glasses, and high-entropy alloys (HEAs). She aims at producing novel nanostructured CoCrFeNiGa magnetic high entropy alloy (Mag HEA) particles and volume MagHEA materials with a large magnetization, high Curie temperature and tuneable coercivity as well as excellent mechanical properties.

Interests of Assoc. Prof. Dr. Mikhail Cherkasskii are focused on the understanding of magnetization nutation in ferromagnets and its coupling to precession and ferromagnetic resonance. He is working on the development of an analytical approach to describe inertial spin dynamics, nutation resonance and collective excitations in ferromagnets.
2020-09-15: Auszeichnung für Priv.-Doz. Dr. Ulf Wiedwald und Kollegen
Mageschneiderte Winzlinge gegen den Krebs
Ihre Nanopartikel aus Gold und Magnetit haben sie speziell für die Diagnose und Therapie von Tumoren entwickelt: Physiker vom Center for Nanointegration (CENIDE) der Universität Duisburg-Essen (UDE) und Moskauer Kollegen werden am 15. September für ihre erfolgreiche Zusammenarbeit ausgezeichnet (CENIDE: News).
2020-07-24: New publication in AIP Advances - Editors Pick!
Reversal of uniaxial magnetic anisotropy in Fe/GaAs (110) films driven by surface relaxation: An in situ ferromagnetic resonance study by Babli Bhagat et al.

Performing in situ studies of ferromagnetic resonance in thin metallic films in ultrahigh vacuum, we found a dramatic change of in-plane magnetic anisotropy in 4 nm Fe film grown on GaAs(110) substrate occurring after deposition. Initially grown, Fe/GaAs(110) film exhibits unusual uniaxial in-plane anisotropy which reverses its sign within 40 hours while the film is kept in vacuum at room temperature. The effect of surface contamination has been excluded using surface-sensitive techniques AES and LEED, which let us to conclude on metastability and ongoing surface relaxation of Fe film. This finding opens up a further study of such island-like grown metastable thin films where magneto-morphological transitions can be altered by temperature and other external stimuli.
2020-05-29: Doktorandenstellen

In unserer Arbeitsgruppe sind Doktorandenstellen zum nächstmäglichen Zeitpunkt zu folgenden Projekten zu besetzen:

B09: "Hierarchical structuring of magnetocaloric materials with nm resolution"

2020-07-03: Neues Gleichstellungsteam
Seit dem 25.09.2019 gibt es an der Fakultt fr Physik ein neues Gleichstellungsteam, darunter auch unsere Mitarbeiterin Dr. Anna Semisalova (rechts), die zusammen mit Dr. Katharina Ollefs und Samira Webers (2. v.l.), die als Stellvertreterinnen zusammen mit Prof. Marika Schleberger (2. v.r.), die Gleichstellungsbeauftragte Cornelia Geller (l.) untersttzen. Ziel ist es, den Grundsatz der Gleichberechtigung von Frauen und Mnner an der Fakultt fr Physik zu bercksichtigen. Darunter versteht sich die Frderung zur Gewinnung und Qualifizierung von Studentinnen und Mitarbeiterinnen und die Vereinbarkeit von Studium, Beruf und Familie zu verbessern.
Link zu Angeboten der Gleichstellung Physik
2020-03-10: Non-standing spin-waves in confined micrometer-sized ferromagnetic structures under uniform excitation
Editors Pick (!) Non-standing spin-waves in confined micrometer-sized ferromagnetic structures under uniform excitation Appl. Phys. Lett. 116, 072401 (2020); https://doi.org/10.1063/1.5139881 Santa Pile et al. A long effort within an international collaboration (U. Linz, Duisburg-Essen, Stanford) including partners from the CRC/TRR 270 broke new ground in element-specific magnetic imaging with picosecond temporal and few nanometer spatial resolution. A non-standing characteristic of directly imaged spin-waves in confined micrometer-sized ultrathin Permalloy (Ni80Fe20) structures is reported along with evidence of the possibility to alter the observed state by modifications to the sample geometry.
2020-03-10: Dynamic unidirectional anisotropy in cubic FeGe with antisymmetric spin-spin-coupling
Nicolas Josten, et al. Scientific Reports 10, 2861, (2020) DOI: 10.1038/s41598-020-59208-8 Successful collaboration with TU-Darmstadt within CRC/TRR 270. We studied bulk polycrystalline B20 FeGe samples prepared in Darmstadt and measured ferromagnetic resonance spectroscopy. As a result we discovered strong (dynamical) unidirectional anisotropy. Such anisotropy is not present in static magnetometry measurements. B20 FeGe exhibits inherent Dzyaloshinskii-Moriya interaction, resulting in a nonreciprocal spin-wave dispersion. By X-band ferromagnetic resonance spectroscopy at 276 K  1 K, near the Curie temperature, a distribution of resonance modes was observed in accordance with the cubic anisotropy of FeGe. This distribution exhibits a unidirectional anisotropy, i.e. shift of the resonance field under field inversion, of KUD = 960 J/m3  10 J/m3, previously unknown in bulk ferromagnets. Additionally, more than 25 small amplitude standing spin wave modes were observed inside a micron sized FeGe wedge, measured at 293 K  2 K. These modes also exhibit unidirectional anisotropy. This effect, only dynamically measurable and not detectable in static magnetometry measurements, may open new possibilities for directed spin transport in chiral magnetic systems.
2020-01-17: Highlighted Publication
The publication based on our long term collaboration with the group of Vernica Salgueirio (university of Vigo, Spain) Shaping iron oxide nanocrystals for magnetic separation applications has been selected to be a part of a themed collection International Year of the Periodic Table: As attractive as magnets applications for magnetic materials. This themed collection is the seventh, and final, in a series celebrating the International Year of the Periodic Table. As Attractive as Magnets Applications for Magnetic Materials features papers from across the Materials and Nano journal portfolio; Materials Horizons, Nanoscale Horizons, Nanoscale, Nanoscale Advances and Journal of Materials Chemistry A, B & C. The papers selected for this themed issue focus on the current hot trends in the field of magnetic materials.
2019-11-26: Cooperate Research Center TRR 270 HoMMage
We celebrate the new Cooperate Research Center TRR 270 HoMMage "Hysteresis Design of Magnetic Materials for Efficient Energy Conversion".
Starting Jan 1st, 2020 we will design and develop magnetic materials for applications in electro mobility, robotics and energy converters over the first period till Dec. 31st , 2023. In our group we have three positions for Ph.D. students available on projects related to this programme (see separate announcements).
2019-09-26: Workshop SpinS-2019 gathers experts in nanomagnetism at the University of Duisburg-Essen

Next week, 2-4 October 2019, more than 40 experts in physics, chemistry and materials science from 12 countries meet in “Die Wolfsburg” Academy in Mülheim an der Ruhr/Duisburg to share their research results and discuss new concepts in nanomagnetism and its applications, like energy-efficient computing and magnetic refrigeration.

The Workshop program covers the most recent experimental and theoretical research developments related to spin phenomena in nanoscale systems as well as the design, properties and applications of magnetic nanomaterials. It includes several emergent technologies based on spin-orbit torques, ultrafast spin dynamics in THz frequency range, magnonics, magnetoacoustics as well as novel materials like shell-ferromagnets, MAX phases (including 2D MXenes), and nanohybrids for theranostics applications actively developed in the working group AG Farle. The SpinS-2019 provides an interdisciplinary platform for meeting the specialists in fabrication and imaging of 2D and 3D magnetic nanostructures, and experts working towards various application areas – from spin dynamics and magnetic memory to additive manufacturing and biomedicine.

The meeting is organized by Michael Farle, Katharina Ollefs and Anna Semisalova, with a technical support of Michael Vennemann and Sabina Grubba. Organizers highly appreciate the financial support of the Center for Nanointegration Duisburg-Essen (CENIDE).

SpinS-2019 website

Flyer

2019-09-26: High Entropy Alloys: How to induce ferromagnetism?
High-entropy alloys are currently the focus of significant attention in materials science and engineering. Some HEAs have considerably better strength-to-weight ratios, with a higher degree of fracture resistance, tensile strength, as well as corrosion and oxidation resistance than conventional alloys. In the recent publication Mehmet Acet showed how to introduce strong magnetism in a Cr20Mn20Fe20Co20Ni20 high-entropy alloy. He could show through the thermal expansion properties that the alloy carries similar anti-Invar properties as FCC-Fe, but unlike FCC-Fe it is stable throughout its solid-state temperature range. Therefore, by exploiting the anti-Invar property and expanding the lattice of the alloy by introducing interstitial carbon, we make Cr20Mn20Fe20Co20Ni20 ferromagnetic with a Curie temperature lying above room temperature. For details see: https://doi.org/10.1063/1.5120251
Picture from Von Shaoqing Wang - Wang, Shaoqing (13 December 2013). "Atomic Structure Modeling of Multi-Principal-Element Alloys by the Principle of Maximum Entropy". Entropy 15 (12): 5536�5548. DOI:10.3390/e15125536., CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=32060405
2019-09-26: A novel concept for bio-inspired architectures
A novel concept for bio-inspired architectures in up-scalable, energy efficient computing is discussed in our recent publication "Biologically encoded magnonics". For details read here (https://www.nature.com/articles/s41467-019-12219-0)
2019-05-20: Magnetite-Gold nanohybrids as ideal all-in-one platforms for theranostics
Maria V. Efremova, Victor A. Naumenko, Marina Spasova, Anastasiia S. Garanina, Maxim A. Abakumov, Anastasia D. Blokhina, Pavel A. Melnikov, Alexandra O. Prelovskaya, Markus Heidelmann, Zi-An Li, Zheng Ma, Igor V. Shchetinin, Yuri I. Golovin, Igor I. Kireev, Alexander G. Savchenko, Vladimir P. Chekhonin, Natalia L. Klyachko, Michael Farle, Alexander G. Majouga and Ulf Wiedwald

was published in Scientific Reports in July 2018 and is listed by the journal among the top 25 articles in the collection 'Chemistry Top 100' articles in 2018. This list is based on most highly accessed chemistry articles covering January-December 2018.
(DOI: 10.1038/s41598-018-29618-w | https://www.uni-due.de/agfarle-archiv/highlights)
2019-04-29: Energy Technology "Best of 2018"
Our review article "Hysteresis Design of Magnetocaloric Materials - From Basic Mechanisms to Applications" Franziska Scheibel, Tino Gottschall, Andreas Taubel, Maximilian Fries, Konstantin P. Skokov, Alexandra Terwey, Werner Keune, Katharina Ollefs, Heiko Wende, Michael Farle, Mehmet Acet, Oliver Gutfleisch, Markus E. Gruner, (Collaboration partners from TU Darmstadt and U. Duisburg-Essen)
published in Energy Technology in 2018 has been named one of the top articles of the year as the "Best of 2018".
This selection is based upon the download and citation numbers as well as the opinions and feedback of the editorial office of the journal.
Understanding hysteresis: Materials with magnetostructural phase transitions (MSPT) show a large magnetocaloric effect (MCE). The understanding of MSPT and its thermal hysteresis requires the knowledge about the electronic, magnetic, and lattice entropy contributions. In this Review, we provide an overview of the properties of MSPT in La-Fe-Si, Heusler alloys, Mn3GaC, and Fe2P‐type materials with respect to the MCE and its reversibility based on studies under static/dynamic conditions at micro‐ and mesoscopic scales.