On-line SPICE-SPIN+X Seminars

On-line Seminar: 26.02.2025 - 15:00 CET

Altermagnetism imaged and controlled down to the nanoscale

Peter Wadley, University of Nottingham

Altermagnetism is a newly identified class of magnetism which combines properties from both ferromagnets and antiferromagnets, making them highly promising candidates for spintronic applications[1,2]. We recently demonstrated the spin split nature of the altermagnetic electronic band structure in MnTe[3]. In this talk, I will discuss how the unique resultant properties of altermagnets can be used to image them in unprecedented details, and also to control them in unique ways.
Utilising a combination of linearly and circularly polarised x-rays we can generate a full Neel vector map of the magnetic domain in MnTe, showing all 6 domain types and revealing vortices and their vorticity. In addition, a combination of patterning and field cooling can control the domain formation to nucleate single domains of our choosing from the micron to nanoscale. This incluides generation and control of the position and vorticity of single vortices. These experiments showcase the unique properties of altermagnets and also provide a platform for the next stages of research and application[4].

 

 

 

 

 

 

 

 

 

Figure1 – Altermagnetic domain structure in open space (a) showing a vortex antivortex pair and (b) in micro-fabricated field-cooled triangles showing single vortices with opposite vorticity. Adapted from [4].

 

 

References
1. Smejkal, L., Sinova, J. & Jungwirth, T. Beyond Conventional Ferromagnetism and Antiferromagnetism: A Phase with Nonrelativistic Spin and Crystal Rotation Symmetry. Physical Review X 12, 031042 (2022).
2. Smejkal, L., Sinova, J. & Jungwirth, T. Emerging Research Landscape of Altermagnetism. Physical Review X 12, 040501 (2022).
3. Altermagnetic lifting of Kramers spin degeneracy
J. Krempaský, L. Šmejkal, S. W. D’Souza, M. Hajlaoui, G. Springholz, K. Uhlířová, F. Alarab, P. C. Constantinou, V. Strocov, D. Usanov, W. R. Pudelko, R. González-Hernández, A. Birk Hellenes, Z. Jansa, H. Reichlová, Z. Šobáň, R. D. Gonzalez Betancourt, P. Wadley, J. Sinova, D. Kriegner, J. Minár, J. H. Dil & T. Jungwirth
Nature 626, 517–522 (2024)
https://doi.org/10.1038/s41586-023-06907-7
4. Altermagnetism imaged and controlled down to the nanoscale
O. J. Amin, A. Dal Din, E. Golias, Y. Niu, A. Zakharov, S. C. Fromage, C. J. B. Fields, S. L. Heywood, R. B. Cousins, J. Krempasky, J. H. Dil, D. Kriegner, B. Kiraly, R. P. Campion, A. W. Rushforth, K. W. Edmonds, S. S. Dhesi, L. Šmejkal, T. Jungwirth, P. Wadley
Nature 636, pages348–353 (2024)

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