TITLE: Magnetothermodynamics: Tuning Heat into Functionalities

AUTHOR: Oksana Fesenko, Madrid Institute of Materials Science (ICMM-CSIC)

WHEN: September, 10 - 12PM

WHERE: Sala de Seminarios, ICMM-CSIC

ABSTRACT: Modern society generates enormous amounts of heat, most of it wasted into the environment, and magnetism offers exciting opportunities to convert it into useful functionalities. Indeed, magnetization and temperature dynamics are two coupled reciprocal phenomena: any magnetization change is accompanied by temperature changes and vice versus. Thus, a key challenge for magnetism is to harness the interplay of heat and spins with the aim is to develop technologies that can exploit, rather than merely dissipate, heat. Based on the modelling results in the group [1-7], I will discuss several of these applications. First, surprisingly, ultrafast heat can excite, drive and switch magnetisation dynamics using low power on unprecedently fast timescale of picoseconds and below that is realized in laser-induced all-optical magnetisation dynamics and switching [1]. Ultrafast heat can nucleate and freeze metastable states such as skyrmions [2] or re-configure spin-ices for neuromorphic computing applications [3].  Secondly, I will discuss the heat gradient-driven dynamics of domain walls and skyrmions in magnetic stripes and cylindrical nanowires (spin-Seebeck effect). The main question here is their direction of their motion, towards hot or cold region [4,5]. Furthermore, magneto-thermoelectric effects allow recovering electricity from heat. Using these effects, thermal magnetometry can 

image nanoscale magnetic textures and even distinguish the domain wall and skyrmion type [6,7]. Finally, motivated by this set-up we propose heat-based nano-oscillators that can convert heat into radio-frequency emission.

References

[1] T. Ostler et al Nature Comm. 3, 666 (2012)

[2] P.Olleros-Rodríguez et al Nanoscale  14, 15701 (2022)

[3] D Pecchio et al Phys. Rev. B 113, 064404 (2026)

[4] E. Raimondo et al  Phys. Rev. Applied 18, 024062 (2022)

[5] E.Saugar et al  Appl. Phys Lett., (2026)

[6] C. Barton et al Sci Adv. 25, eadc9798 (2022)

[7] Ch. Barker et al, Appl. Phys. Lett. 127, 152405 (2025)