SPICE Workshop on Spin textures: Magnetism meets Plasmonics, July 23rd - 25th 2024
Naëmi Leo
While a moderate temperature increase usually does not alter a micromagnetic state directly it does modify material properties and can affect magnetisation dynamics and switching kinetics. As such, local heating can provide an interesting means to enhance nanomagnetic functionalities. However, contemporary heating methods have significant drawbacks when considering integration in nanoscale devices, as they are either slow, prone to damage, or cannot be reliably aligned with nanoscale magnetic features (such as domain walls or other spin textures). Furthermore, the respective spatial temperature profiles of conventional heating methods cannot be adapted in-situ.
Disadvantages of global heating schemes can be overcome by drawing inspiration from the emerging field of thermoplasmonics [1]. Here, light-induced excitation of localised surface plasmon resonances and subsequent dissipation of internal currents results in fast (down to ps) and effective local heating (with temperature increases of several 100 K possible). Using experimental degrees of freedom, thermoplasmonic nanoparticles thus allow versatile temperature control on nano- to millimetre length scales, which can be reconfigured via light wavelength, light polarisation, and focal position.
In this tutorial I will introduce the basic concepts to creating hybrid magneto-thermoplasmonic devices [2]. As a new pathway to combining opto-electronics with spintronics, I will discuss potential applications that might benefit from light-induced thermal remote control. In particular focussing on perspectives to non-conventional computing devices, I will present an example of an optically reconfigurable nanomagnetic Boolean OR/AND gate with nanosecond operation at picojoule energies that result in a non-volatile output state [3].
References:
[1] G. Baffou, Thermoplasmonics: Heating Metal Nanoparticles using Light. Cambridge University Press (2017).
[2] M. Pancaldi, N. Leo, and P. Vavassori, Nanoscale 11, 7656 (2019).
[3] P. Gypens, N. Leo, M. Menniti, P. Vavassori, and J. Leliaert, Phys. Rev. Appl. 18 024014 (2022).