Seminar experimentelle Physik der kondensierten Materie

This Friday, the 26th, from 12 to 2 pm, Kilian Leutner and Thomas Winkler will give a test run of the "Intermag 2024 Hands-on session: AI in magnetism." We will give an introductory talk (~30 minutes) about AI in magnetism and more concrete information about our recent project: "AI-accelerated detection of spin structures in Kerr-microscopy data." Afterward, we will ask you to open your laptops and participate actively in the AI revolution. We will guide you through our repository. The goal is that participants can infer data and even train models on their own at the end of the session. If you are interested, feel free to have a look at our paper and official repository: Paper: Labrie-Boulay et al., Phys. Rev. Appl. 21, 014014 (2024): https://doi.org/10.1103/PhysRevApplied.21.014014 Repository (v2.0): Winkler et al., Zenodo repository: https://doi.org/10.5281/zenodo.10997175 If you would like to join, please send an email to Kilian Leutner ( kileutne@students.uni-mainz.de ) by Thursday. Kilian Leutner will eventually send around links for a smaller data repository, install instructions this week for the session. You can participate in this session at the Physics building in Mainz in the “Medienraum” (03-431), or you can access the session via Teams using the following link: https://teams.microsoft.com/l/meetup-join/19%3ameeting_MTRhNjI4ZWYtNDkyMC00YzQ1LWIyNzgtMzkxNjAzYjNjYjY2%40thread.v2/0?context=%7b%22Tid%22%3a%2251aa2b30-c9fa-40db-b91a-3a53a8a08d85%22%2c%22Oid%22%3a%22e50b859d-212d-4ce0-b8ca-82e26bd02e43%22%7d . (As this is a test talk, we are also happy about some feedback)

This Friday, the 26th, from 12 to 2 pm, Kilian Leutner and Thomas Winkler will give a test run of the "Intermag 2024 Hands-on session: AI in magnetism." We will give an introductory talk (~30 minutes) about AI in magnetism and more concrete information about our recent project: "AI-accelerated detection of spin structures in Kerr-microscopy data." Afterward, we will ask you to open your laptops and participate actively in the AI revolution. We will guide you through our repository. The goal is that participants can infer data and even train models on their own at the end of the session. If you are interested, feel free to have a look at our paper and official repository: Paper: Labrie-Boulay et al., Phys. Rev. Appl. 21, 014014 (2024): https://doi.org/10.1103/PhysRevApplied.21.014014 Repository (v2.0): Winkler et al., Zenodo repository: https://doi.org/10.5281/zenodo.10997175 If you would like to join, please send an email to Kilian Leutner ( kileutne@students.uni-mainz.de ) by Thursday. Kilian Leutner will eventually send around links for a smaller data repository, install instructions this week for the session. You can participate in this session at the Physics building in Mainz in the “Medienraum” (03-431), or you can access the session via Teams using the following link: https://teams.microsoft.com/l/meetup-join/19%3ameeting_MTRhNjI4ZWYtNDkyMC00YzQ1LWIyNzgtMzkxNjAzYjNjYjY2%40thread.v2/0?context=%7b%22Tid%22%3a%2251aa2b30-c9fa-40db-b91a-3a53a8a08d85%22%2c%22Oid%22%3a%22e50b859d-212d-4ce0-b8ca-82e26bd02e43%22%7d . (As this is a test talk, we are also happy about some feedback)

In this talk, I will first discuss several progresses made in our group about fundamental properties of skyrmions in chiral magnetic films. These include 1) skyrmion sizes in isolated, in crystal, or in stripy forms; 2) skyrmion nucleation, formation, and potential barrier energies; 3) the roles of magnetic field in skyrmion crystal formation; 4) the stability and existing conditions of composite skyrmions such as target skyrmions and skyrmion bags/cluster; 5) topological equivalence of stripy phases and skyrmion crystals. Then I will discuss a new theory about widely observed unusual anisotropic magnetoresistance (UAMR) in bilayers which leads to the notion of the spin-Hall MR (SMR) in the famous SMR theory. The theory is based on the universal features in all bilayer heterostructure: resistivity tensor depends on magnetization and interfacial field. I will show that the angular dependencies of UAMR do not depend on the microscopic details, thus are universal. Experiments that can test this theory against the SMR theory are also proposed. ** This work is supported by the National Key Research and Development Program (No. 2020YFA0309600), the NSFC Grant (No. 11974296), and HK RGC Grants (No. 16300523, 16300522, and 16302321).

I will review our recent work that aims at harvesting quantum fluctuations of magnetic systems, with both quantum information and many-body physics in mind. Focusing on magnons as building blocks of collective spin dynamics in magnetic insulators, I will discuss the prospects of their scalable integration with proximal color centers, such as nitrogen-vacancy impurities, using the latter as either quantum sensors, which can be operated in a range of different physical modalities, or qbits, whose entangled dynamics is governed by the common dissipative magnonic environment. Recent experiments on using color centers as spectrally-resolved sensors of magnetic dynamics demonstrate their strong coupling with a range of 2D materials. Inspired in part by the ideas from quantum optics, we are now pursuing the inverse functionality: imprinting collective noise of the tunable environment onto emergent many-body properties of color-center ensembles.

Energy-efficient spintronic devices require a large spin-orbit torque (SOT) and low damping to excite magnetic precession. In conventional devices based on heavy-metal/ferromagnet bilayers, reducing the ferromagnet thickness to ~1 nm enhances the torque – but dramatically increases the damping. I will present my team’s new approach toward attaining low damping and a sizable SOT in single-layer, 10-nm-thick FeNi alloys. A vertical Fe:Ni compositional gradient is designed to provide the necessary asymmetry for SOT generation. We confirm low effective damping in FeNi even with a steep compositional gradient. More remarkably, we reveal a sizable anti-damping SOT even without any intentional compositional gradient. Through noninvasive depth-profile measurements, we identify a lattice strain gradient as the key asymmetry giving rise to the SOT. Our findings provide fresh insights into damping and SOTs in single-layer ferromagnets for power-efficient spintronic devices.

Ever wondered how influential journals select content for publication and how peer review works? In this talk, I will discuss the editorial process at these journals, which typically rely on professional editors, focusing in particular on the Cell Press portoflio and introducing Newton, our new flagship physics journal. I will also share my views on current trends in scientific publishing, and provide tips on how to maximise the fit of your manuscript for high-impact journals and on how to deliver an appropriate reviewer report if you are invited to review a manuscript.