Third Funding Period 2024-2027:
B03 Spin+Non-Equilibrium: Ultrafast angular momentum transfer between electron, magnons, and phonons
Prof. Dr. Hans Christian Schneider (Department of Physics, RPTU)
Prof. Dr. Bärbel Rethfeld (Department of Physics, RPTU)
Prof. Dr. Benjamin Stadtmüller (Department of Physics, RPTU)
Project B03 deals with orbital angular-momentum conversion processes between electrons, magnons and phonons after ultrashort-pulse excitation in ferromagnets. We focus on the role of polarized phonons and photons with orbital angular momentum in the demagnetization and remagnetization dynamics. Theoretically and experimentally, we will investigate the key signatures of polarized phonons, and their interplay with magnons across different timescales ranging from the ultrafast far-from-equilibrium to the close-to-equilibrium regime. We will develop a comprehensive theoretical understanding that connects femto-magnetism to magnonics and the phenomenological Landau-Lifschitz-Gilbert equation.
Second Funding Period 2020-2023:
B03 Spin+Non-Equilibrium: Ultrafast non-equilibrium and transport
Prof. Dr. Hans Christian Schneider (Department of Physics, RPTU)
Prof. Dr. Bärbel Rethfeld (Department of Physics, RPTU)
Prof. Dr. Benjamin Stadtmüller (Department of Physics, RPTU)
Project B03 aims at understanding of far-from-equilibrium dynamics in ferromagnetic metals and ferromagnet-metal multilayers, in particular, magnetization dynamics and spin-dependent transport as they occur after ultrashort-pulse excitations and mainly on ultra-fast timescales. The theory part of this project investigates electron-magnon interactions and combines Boltzmann transport equations, stochastic methods, and macroscopic approaches to cover electronic spin dynamics in metallic systems on all relevant energy scales. Experimentally, electronic dynamics far from equilibrium are studied using a novel method based on the ultrafast magneto-optical Kerr effect with depth resolution.
First Funding Period 2016-2019:
B03 Spin+Non-Equilibrium: Ultrafast non-equilibrium spin and charge transport
Prof. Dr. Hans Christian Schneider (Department of Physics, RPTU)
Prof. Dr. Bärbel Rethfeld (Department of Physics, RPTU)
JProf. Dr. Benjamin Stadtmüller (Department of Physics, RPTU)
Project B03 is concerned with a comprehensive investigation of spin and charge transport in magnetic multilayer structures under pronounced non-equilibrium conditions created by ultra-short optical pulses. In this case, high densities of hot carriers far away from the Fermi energy are created, which start to move ballistically through the structure, but also undergo spin-dependent relaxation processes. Thus, our understanding of spin transport in magneto-electronic devices is not applicable here. The theory part of this project combines complementary methods to cover a wide range of excitations from close to the Fermi level, where the details of the band structure are important, to high energies, where plasma-like models can be applied. For this variety of excitation conditions, hot-electron transport is studied experimentally using a novel method based on the ultrafast magneto-optical Kerr effect with depth resolution.
Aim 1: Understanding of the role of non-equilibrium in spin-resolved hot electron transport in homogeneous metals
Aim 2: Characterization of time-dependent spin and charge transport through interfaces and multilayer structures
Aim 3: Development of numerically easily tractable macroscopic approaches to model time-dependent spin-transport for a broad range of excitation conditions of different magnetic multilayers