Slaven Garaj

@article{ISI:001449775100029,
title = {Ultrafast thermo-optical control of spins in a 2D van der Waals semiconductor},
author = {Maciej Dabrowski and Sumit Haldar and Safe Khan and Paul S Keatley and Dimitros Sagkovits and Zekun Xue and Charlie Freeman and Ivan Verzhbitskiy and Theodor Griepe and Unai Atxitia and Goki Eda and Hidekazu Kurebayashi and Elton J G Santos and Robert J Hicken},
doi = {10.1038/s41467-025-58065-1},
times_cited = {7},
year = {2025},
date = {2025-03-21},
journal = {NATURE COMMUNICATIONS},
volume = {16},
number = {1},
publisher = {NATURE PORTFOLIO},
address = {HEIDELBERGER PLATZ 3, BERLIN, 14197, GERMANY},
abstract = {Laser pulses provide one of the fastest means of manipulating electron spins in magnetic compounds and pave the way to ultrafast operation within magnetic recording, quantum computation and spintronics. However, effective management of the heat deposited during optical excitation is an open challenge. Layered two-dimensional (2D) van der Waals (vdW) materials possess unique thermal properties due to the highly anisotropic nature of their chemical bonding. Here we show how to control the rate of heat flow, and hence the magnetization dynamics, induced by an ultrafast laser pulse within the 2D ferromagnet Cr2Ge2Te6. Using time-resolved beam-scanning magneto-optical Kerr effect microscopy and microscopic spin modelling calculations, we show that by reducing the thickness of the magnetic layers, an enhancement of the heat dissipation rate into the adjacent substrate leads to a substantial reduction in the timescale for magnetization recovery from several nanoseconds down to a few hundred picoseconds. Finally, we demonstrate how the low thermal conductivity across vdW layers may be used to obtain magnetic domain memory behaviour, even after exposure to intense laser pulses. Our findings reveal the distinctive role of vdW magnets in the ultrafast control of heat conduction, spin dynamics and non-volatile memory.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

@article{ISI:001273247900001,
title = {Spin-Glass States Generated in a van der Waals Magnet by Alkali-Ion Intercalation},
author = {Safe Khan and Eva S Y Aw and Liam A V Nagle-Cocco and Aakanksha Sud and Sukanya Ghosh and Mohammed K B Subhan and Zekun Xue and Charlie Freeman and Dimitrios Sagkovits and Araceli Gutierrez-Llorente and Ivan Verzhbitskiy and Daan M Arroo and Christoph W Zollitsch and Goki Eda and Elton J G Santos and Sian E Dutton and Steven T Bramwell and Chris A Howard and Hidekazu Kurebayashi},
doi = {10.1002/adma.202400270},
times_cited = {5},
issn = {0935-9648},
year = {2024},
date = {2024-07-22},
journal = {ADVANCED MATERIALS},
volume = {36},
number = {36},
publisher = {WILEY-V C H VERLAG GMBH},
address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY},
abstract = {Tuning magnetic properties in layered van der Waals (vdW) materials has captured significant attention due to the efficient control of ground states by heterostructuring and external stimuli. Electron doping by electrostatic gating, interfacial charge transfer, and intercalation is particularly effective in manipulating the exchange and spin-orbit properties, resulting in a control of Curie temperature (TC) and magnetic anisotropy. Here, an uncharted role of intercalation is discovered to generate magnetic frustration. As a model study, Na atoms are intercalated into the vdW gaps of pristine Cr2Ge2Te6 (CGT) where generated magnetic frustration leads to emerging spin-glass states coexisting with a ferromagnetic order. A series of dynamic magnetic susceptibility measurements/analysis confirms the formation of magnetic clusters representing slow dynamics with a distribution of relaxation times. The intercalation also modifies other macroscopic physical parameters including the significant enhancement of TC from 66 to 240 K and the switching of magnetic easy-hard axis direction. This study identifies intercalation as a unique route to generate emerging frustrated spin states in simple vdW crystals.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}