On-line SPICE-SPIN+X Seminars
On-line Seminar: 28.02.2024 - 15:00 CET
TBA
Dirk Grundler, EPFL
TBA
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Spin-X-Abstracts
On-line SPICE-SPIN+X Seminars
On-line Seminar: 07.02.2024 - 15:00 CET
TBA
Youn Jue Bae, Cornell
TBA
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On-line SPICE-SPIN+X Seminars
On-line Seminar: 14.02.2024 - 15:00 CET
TBA
Yaroslav Tserkovnyak, UCLA
TBA
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On-line SPICE-SPIN+X Seminars
On-line Seminar: 13.03.2024 - 15:00 CET
TBA
Joerg Wunderlich, University of Regensburg
TBA
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On-line SPICE-SPIN+X Seminars
On-line Seminar: 31.01.2024 - 15:00 CET
TBA
Tom Seifert, FU Berlin
TBA
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On-line SPICE-SPIN+X Seminars
On-line Seminar: 13.12.2023 - 15:00 CET
First-principles calculations of spin transport and spin-orbit torque in metallic heterostructures
Kirill Belashchenko, University of Nebraska–Lincoln
I will discuss first-principles calculations of spin transport and spin-orbit torques in disordered films and multilayers within the nonequilibrium Green's function technique with supercell disorder averaging. I will present the results for ferromagnet/nonmagnet bilayers, for a single platinum film, and for ferromagnet/nonmagnet/ferromagnet trilayers, highlighting the features that can't be easily explained within the conventional spin-diffusion model. I will also discuss the possibility of using ferromagnets with anisotropic transport spin polarization as sources of exchange-driven transverse spin current, supported by a computational screening of suitable materials.
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On-line SPICE-SPIN+X Seminars
On-line Seminar: 22.11.2023 - 15:00 CET
Spin transport in graphene-based van der Waals heterostructures
Talieh Ghiasi, Harvard
Decades of research in graphene nanodevices have shown that graphene is an excellent material for charge and spin transport thanks to its high charge carrier mobility and long spin lifetime. However, practical applications of graphene-based spintronic devices require efficient electrical control of the spin information. This sought-after goal is now achievable through the proximity of graphene to other two-dimensional materials in van der Waals heterostructures. In this talk, I will show how we enrich the properties of graphene by the proximity effect and induce coupling between charges and spins via spin-orbit [1, 2] and exchange [3, 4] interactions.
These interactions result in the emergence of various unprecedented phenomena in graphene that showcase its active role in generating spin currents, both electrically and thermally [3, 4]. We further explore quantum Hall transport in proximitized graphene aiming to achieve quantum coherent spin propagation in these heterostructures. These experimental advancements in spin-related functionalities of graphene-based nanodevices can have potential applications in future ultra-compact memory and computing systems.
[1] Ghiasi, TS, et al. Nano Letters 17, 7528 (2017)[2] Ghiasi, TS, et al. Nano Letters 19, 5959 (2019)
[3] Ghiasi, TS, et al. Nature Nanotechnology 16, 788 (2021)
[4] Kaverzin, AA, et al. 2D Materials 9, 045003 (2022)
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On-line SPICE-SPIN+X Seminars
On-line Seminar: 29.11.2023 - 15:00 CEST
Thermal and Electrical Probes of Spin Effects in Antiferromagnets: a Revisitation and a New Idea?
Barry Zink, University of Denver
The thermal injection of spin currents across an interface from insulators with a wide range of magnetic ordered states into metals that convert this spin to measurable charge, is known as the longitudinal spin Seebeck effect (LSSE). This effect has proven to be a powerful means to probe the fundamental spin properties of magnetically ordered materials. In recent years, the LSSE and its related electrical effect, spin Hall magnetoresistance (SHMR), have proven especially interesting in a range of antiferromagnetic materials, which can be difficult to probe using more traditional magnetic characterization techniques. In this talk, the first focus is on spin-charge conversion in polycrystalline chromium, an antiferromagnetic metal. Our recent studies using standard [1] and local-heating LSSE techniques [2] show that antiferromagnetism may play a role in the spin-conversion, which was not apparent from earlier work on this material. SHMR measurements made as part of the locally-heated LSSE show unexpected symmetries that may also relate to a role for AFM order. I will then discuss ongoing work on related probes of antiferromagnetic spin effects in field-controllable coupled AFM/FM perovskite oxide systems. Here, dramatic field dependence of the electrical Hall signals are seen when Pt is in contact with the material, while absence of Pt or presence of metals that disturb the AFM order change both the signal sizes and field symmetry. This suggests new routes to low-field control of spin transport in such coupled FM/AFM oxide systems. This work is supported by the US National Science Foundation (DMR-2004646 and EECS-2116991)
[1] S. M. Bleser et al, Journal of Applied Physics. 131, 113904 (2022).[2] S. M. Bleser, et al, in preparation
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On-line SPICE-SPIN+X Seminars
On-line Seminar: 08.11.2023 - 15:00 CET
Probabilistic Computing with p-bits: Optimization, Machine Learning and Quantum Simulation
Kerem Çamsarı, University of California
The slowing down of Moore's era has coincided with escalating computational demands from Machine Learning and Artificial Intelligence. An emerging trend in computing involves building physics-inspired computers that leverage the intrinsic properties of physical systems for specific domains of applications. Probabilistic computing with p-bits, or probabilistic bits, has emerged as a promising candidate in this area, offering an energy-efficient approach to probabilistic algorithms and applications.
Several implementations of p-bits, ranging from standard CMOS technology to nanodevices, have been demonstrated. Among these, the most promising p-bits appear to be based on stochastic magnetic tunnel junctions (sMTJ). sMTJs harness the natural randomness observed in low barrier nanomagnets to create energy-efficient and fast fluctuations, up to GHz frequencies. In this talk, I will discuss how magnetic p-bits can be combined with conventional CMOS to create hybrid probabilistic-classical computers for various applications. I will provide recent examples of how p-bits are naturally applicable to combinatorial optimization, such as solving the Boolean satisfiability problem, energy-based generative machine learning models like deep Boltzmann machines, and quantum simulation for investigating many-body quantum systems.
Through experimentally-informed projections for scaled p-computers using sMTJs, I will demonstrate how physics-inspired probabilistic computing can lead to GPU-like success stories for a sustainable future in computing.
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On-line SPICE-SPIN+X Seminars
On-line Seminar: 24.01.2024 - 15:00 CET
Orbital Angular Momentum for Spintronics
Mathias Kläui, JGU Mainz
TBA
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