Nanoscale Confinement Enhances Ultrafast Demagnetization
Abstract
Nanoscale miniaturization has revolutionized the field of spintronics by enabling exponential growth in areal bit density. A similar leap is also expected in device speeds through successfully harnessing femtosecond magnetization dynamics. However, combining this with the miniaturization of realistic devices is challenging. To address this, we studied the effect of dimensional confinement on the femtosecond demagnetization of Fe. By gradually increasing the level of confinement while keeping excitation conditions constant, we found that Fe layers thinner than 10 nm exhibit enlarged demagnetization amplitudes, reaching a increase at 2 nm. By combining ultrafast experiments sensitive to the spins, the charge carriers, and the phonons, we establish that this finitesize effect is magnetic in origin and is not phonondriven. With the support of abinitio calculations and atomistic spin dynamics simulations, we identify the enhancement effect as due to local weakening of spin order at the Fes interface, which becomes significant upon increased confinement.
Cite
@article{arxiv.2605.28307,
title = {Nanoscale Confinement Enhances Ultrafast Demagnetization},
author = {Yoav William Windsor and Tobias Lojewski and Moumita Kundu and Klaus Sokolowski-Tinten and Nico Rothenbach and Andrea Eschenlohr and Markus Ernst Gruner and Katharina Ollefs and Carolin Schmitz-Antoniak and Soma Salamon and Daniela Zahn and Laurenz Rettig and Christian Schüßler-Langeheine and Niko Pontius and Renkai Li and Mianzhen Mo and Suji Park and Xiaoshe Shen and Stephen Weathersby and Xijie Wang and Rossitza Pentcheva and Heiko Wende and Ulrich Nowak and Uwe Bovensiepen},
journal= {arXiv preprint arXiv:2605.28307},
year = {2026}
}