Electrical and current-gradient control of the orbital torque with light elements

ORBIS Doctoral Network; Albert; Sur place; EUR 19 000 - 23 000; Plein temps

Résumé du poste

ORBIS Doctoral Network at Laboratoire Albert Fert (Université Paris-Saclay, CNRS) is offering a PhD project focusing on orbital polarization and orbital torques in spintronic devices. The research aims to engineer metal stacks and explore low-energy writing using OT, with strong emphasis on fundamental physics and potential applications in ICT and quantum technologies.

The project will employ harmonic Hall, spin pumping, FMR linewidth analysis, and ultrafast THz-TDS, while incorporating

Qualifications

• Master 2 in condensed-matter physics (Experimental).

Responsabilités

• Optimize metal stacking to promote orbital polarization.
• Demonstrate enhanced efficiency or figures of merit of stacks.
• Apply techniques such as harmonic Hall, spin pumping, FMR, THz-TDS and compare orbital vs spin contributions.
• Design 200 nm or smaller memory elements using e-beam lithography for low-energy writing.
• Develop theory/numerical simulations and possibly DFT outputs.

Connaissances

Experimental physics

Spintronics techniques

Formation

Master 2 in condensed-matter physics (Experimental)

Outils

Harmonic Hall

Spin pumping

FMR linewidth analysis

THz-TDS

Description du poste

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

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

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