On-line SPICE-SPIN+X Seminars

On-line Seminar: 21.01.2026 - 15:00 CET

Orbital-to-spin conversion in magnetic heterostructures

Pietro Gambardella, Department of Materials, ETH Zurich, Switzerland

Spin-orbital torques are central to spintronics, enabling current-induced magnetization switching, excitation of spin waves, and manipulation of noncollinear spin textures in nanoscale devices [1]. Besides the electron’s spin, recent investigations have pointed out the importance of the orbital degree of freedom in generating and transferring angular momentum from charge currents to spin systems. The generation and transport mechanisms of nonequilibrium orbital momenta are currently heavily debated. This talk will discuss the related issue of orbital-to-spin conversion, which is relevant for orbital transport, torques, and pumping phenomena. Experimental examples will include nonmagnetic/ferromagnetic bilayers [2,3], ferrimagnetic alloys [4] and garnets [5], and antiferromagnets [6].

References:

[1] Current-induced spin-orbit torques in ferromagnetic and antiferromagnetic systems, A. Manchon, J. Železný, I.M. Miron, T. Jungwirth, J. Sinova, A. Thiaville, K. Garello, and P. Gambardella, Rev. Mod. Phys. 91, 035004 (2019).

[2] Giant orbital Hall effect and orbital-to-spin conversion in 3d, 5d, and 4f metallic heterostructures, G. Sala and P. Gambardella, Phys. Rev. Res. 4, 033037 (2022).

[3] Mitigation of Gilbert damping in the CoFe/CuOx orbital torque system, S. Ding, H. Wang, W. Legrand, P. Noël, and P. Gambardella, Nano Lett. 24, 10251 (2024).

[4] Orbital Torque in Rare-Earth Transition-Metal Ferrimagnets, S. Ding, M.-G. Kang, W. Legrand, and P. Gambardella, Phys. Rev. Lett. 132, 236702 (2024).

[5] Orbital pumping in ferrimagnetic insulators, H.Wang, M.-G. Kang, D. Petrosyan, S. Ding, R. Schlitz, L.J. Riddiford, W. Legrand, and P. Gambardella, Phys. Rev. Lett. 134, 126701 (2025).

[6] Generation, transmission, and conversion of orbital torque by an antiferromagnetic insulator, S. Ding, P. Noël, G. K. Krishnaswamy, N. Davitti, G. Sala, M. Fantauzzi, A. Rossi, P. Gambardella, Nat. Comm. 16, 9239 (2025).

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On-line SPICE-SPIN+X Seminars

On-line Seminar: 28.01.2026 - 15:00 CET

Orbital ordering-induced unconventional magnetism

Johannes Knolle, TU Munich

Altermagnetism has emerged as a third type of collinear magnetism. In contrast to standard ferromagnets and antiferromagnets, altermagnets exhibit extra even-parity wave spin order parameters resulting in a spin splitting of electronic bands in momentum space. In real space, sublattices of opposite spin polarization are anisotropic and related by rotational symmetry. In the hitherto identified altermagnetic candidate materials, the anisotropies arise from the local crystallographic symmetry. Here, we show that altermagnetism can also form as an interaction-induced electronic instability in a lattice without the crystallographic sublattice anisotropy. We discuss different microscopic examples of orbital-induced altermagnetism and promising experimental directions.

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On-line SPICE-SPIN+X Seminars

On-line Seminar: 03.06.2026 - 15:00 CEST

Topology and orbital piezomagnetism in altermagnets

Jörn Venderbos, Drexel

The discovery of altermagnets has revealed intriguing properties of magnetic materials which expose connections with other phenomena. Perhaps the most interesting and consequential connection is that between altermagnetism and topology. This talk will discuss the connection between altermagnetism and topology, in particular from the perspective of minimal miscroscopic models in two dimensions. Special attention will be given to the way in which electronic topology is reflected in orbital piezomagnetism.

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On-line SPICE-SPIN+X Seminars

On-line Seminar: 15.07.2026 - 15:00 CET

What do minimal models tell us about non-relativistic spin-splittings?

Daniel F. Agterberg, UW

Altermagnets and odd-parity magnets have recently emerged as important classes of magnetic materials for spintronics due to their vanishing net magnetization and large, strongly momentum dependent, energy splittings between opposite spin electronic states.   Most existing theoretical research on these magnetic states stems from density functional theory (DFT). Here I present recent progress [1,2,3] on developing Hubbard Hamiltonians for non-relativistic spin-splitting with an emphasis on odd-parity magnets. These Hubbard Hamiltonians realize lattice doubling antiferromagnet states that provide microscopic descriptions for p-wave, f-wave, and h-wave odd-parity magnets. I provide insight into the stability, the microscopic origin of the odd-parity electronic spin-textures, and response properties of these states.  Finally, I reveal theories of related period doubling antiferromagnets that do not exhibit any spin-splitting, but give rise to a Berry-curvature dipole, ferroaxial order, or spontaneous spin-orbit coupling  [4,5].

[1] Minimal models for altermagnetism, M. Roig, A. Kreisel, Y. Yu, B. M. Andersen, and D. F. Agterberg, Phys. Rev. B 110, 144412 (2024).
[2] Odd-parity magnetism driven by antiferromagnetic exchange, Y. Yu, M.B. Lyngby, T. Shishidou, M. Roig, A. Kreisel, M.  Weinert, B. M. Andersen, D. F. Agterberg, Phys. Rev Lett. 135, 046701 (2025).
[3] Odd-Parity Magnetism in Fe-Based Superconductors, R. Dsouza, A. Kreisel, B. M. Andersen, D. F. Agterberg, and M. H. Christensen, Phys. Rev. B 113, 144509 (2026).

[4] Parity and time-reversal invariant Ising spin ordering, Yue Yu, Jin Matsuda, Hikaru Watanabe, Ryotaro Arita, and Daniel F. Agterberg, arXiv:2603.12330

[5] Ferroaxial magnets: time-reversal-even mirror symmetry violation from spin order, Hikaru Watanabe, Yue Yu, Jin Matsuda, Daniel F. Agterberg, and Ryotaro Arita, arXiv:2603.12502

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On-line SPICE-SPIN+X Seminars

On-line Seminar: 01.07.2026 - 15:00 CEST

Topology and persistent spin currents in superconducting altermagnets

Marcel Franz, UBC

At low temperature, altermagnetic metals can naturally support spin-triplet superconducting phases with, effectively,  independent condensates for spin-up and spin-down electrons. I will show that such a state exhibits non-trivial topology. In addition it can be used to both generate and carry spin-polarized persistent currents that are of interest to spintronic applications.  Theses conclusions apply to altermagnets that become intrinsically superconducting at low temperatures, but, remarkably, also to the case when an altermagnet is proximitized with a conventional spin-singlet s-wave superconductor. 

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On-line SPICE-SPIN+X Seminars

On-line Seminar: 08.04.2026 - 15:00 CEST

Altermagnetism: an unconventional quantum state of matter

Rafael Fernandes, UIUC

Magnetism is the posterchild of how the interplay between electron-electron interactions and quantum physics promotes novel macroscopic phenomena. Historically, the evolution of our understanding of magnetism has been related to the discovery of new paradigms in condensed-matter physics, as exemplified by the connections between antiferromagnetism and Mott insulators, spin glasses and non-ergodic states, and spin liquids and fractionalized excitations. Recently, a new framework proposed to classify magnetic phases brought renewed interest in unconventional magnetic states, which are qualitatively distinct from ferromagnets and standard Néel antiferromagnets. Among those, altermagnetic phases have been met with enthusiasm by the scientific community, as they display properties found in both ferromagnets (like the splitting of electronic bands with opposite spins) and conventional antiferromagnets (like the absence of a net magnetization). Formally, what distinguishes these three different magnetic states are the crystalline symmetries that, when combined with time reversal, leave the system invariant. In the case of altermagnets, because these symmetries involve rotations, the system is endowed with unique properties such as nodal spin-splitting and piezomagnetism. In this talk, I will introduce the concept of altermagnetism and discuss its connection to long-standing problems in the field of quantum materials, such as multipolar magnetism and electronic liquid-crystalline phases. I will also present the predicted experimental signatures of altermagnetic order in thermodynamic and transport properties, and show that altermagnets provide a fertile ground to realize non-trivial topological and superconducting phenomena in quantum materials.

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