IRP4
experimental project
Electrical and current-gradient control of the orbital torque with light elements
Location
Palaiseau, France
Host institution
CNRS is a government-funded research organization under the administrative supervision of the French Ministry of Higher Education. It is the largest fundamental research organization in Europe.
Laboratoire Albert Fert focuses on various areas of condensed matter physics, i.e. spintronics, oxytronics, superconductivity and, more recently, neuromorphic physics, in which the laboratory is at the forefront in France and internationally. This fundamental research is also aimed at developing applications and stimulating innovation in ICT, unconventional approaches to computing and beyond CMOS logic, and quantum technologies.
Supervisor
Dr. Henri Jaffrès
Description
The use of the orbital polarization and orbital torques (OT) represents a clear perspective to enhance operations efficiency of spintronic devices. The reason is that the generation of our-of-equilibrium orbital polarization, unlike the spin counterpart, does not require the action of any spin-orbit coupling as a perturbation, to be implemented. With the OT, one can already anticipate a severe reduction of the critical currents for magnetization switching in corresponding devices.
In this project, we first plan to make optimized engineering of metal stacking involving light elements promoting the required orbital polarization and demonstrate the enhancement of the efficiency or figure of merit of the stacks. Moreover, (ii) by using and combining various experimental techniques and methods available at the laboratory (harmonic Hall, spin pumping, FMR linewidth analysis) among which ultrafast optical excitation (THz-TDS), we will benchmark the orbital generation, propagation and orbital currents and corresponding torque efficiencies (orbital Hall angle, orbital Rashba-Edelstein length, decoherence length) in these multilayers and at their interfaces. We will design on 200 nm or less magnetic memory elements made by e-beam lithography to achieve the proof of concept of low energy writing operation using the OT. The third part (iii) of the experimental task will be to introduce and demonstrate a gate voltage control of the OT-driven magnetization switching. (iv) The overall following data and analyses of the different physical effects (orbital vs. Spin contribution) will be accompanied by the development of advanced theory/model/numerical simulations and possibly DFT output.
Requirements
Level: Master 2 in condensed-matter physics (Experimental)
Planned Secondments
- Academic secondment at Freie Universität Berlin, under the supervision of Tobias Kampfrath,
- Industrial secondment at Singulus Technologies AG, under the supervision of Jürgen Langer
Planned Secondments
Academic Secondment
Freie Universität Berlin (FUB)
Berlin, Germany
Prof. Tobias Kampfrath | Dr. Tom S. Seifert
Industrial Secondment
Singulus Technologies AG (STAG)
Kahl am Main, Germany
Dr. Jürgen Langer | Dr. Berthold Ocker
Registering University
Université Paris-Saclay
