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A closed system of the equations for the local Bloch vectors and spin correlation functions is obtained by decomplexification of the Liouville-von Neumann equation for 4 magnetic particles with the exchange interaction that takes place in…

Statistical Mechanics · Physics 2011-07-05 E. A. Ivanchenko

It is generally accepted that the effective magnetic field acting on a magnetic moment is given by the gradient of the energy with respect to the magnetization. However, in ab initio spin dynamics within the adiabatic approximation, the…

A joint theoretical and experimental investigation is performed to understand the underlying physics of laser-induced demagnetization in Ni and Co films. Experimentally dynamics of spins is studied by determining the time-dependent…

It is found that subtle changes in the external magnetic field and temperature result in dramatic changes in the ultrafast response of spins to a femtosecond laser excitation in a ferrimagnetic Gd/FeCo multilayer. A total of six distinct…

Materials Science · Physics 2024-11-25 T. G. H. Blank , B. D. Muis , T. Lichtenberg , B. Koopmans , A. V. Kimel

We present a theory of out-of-equilibrium ultrafast spin dynamics in magnetic heterostructures based on the s-d model of ferromagnetism. Both in the bulk and across interfaces, the exchange processes between the itinerant s and the…

Mesoscale and Nanoscale Physics · Physics 2015-12-02 Erlend G. Tveten , Arne Brataas , Yaroslav Tserkovnyak

The ultrafast manipulation of magnetic order due to optical excitation is governed by the intricate flow of energy and momentum between the electron, lattice and spin subsystems. While various models are commonly employed to describe these…

The ability to drive a spin system to state far from the equilibrium is indispensable for investigating spin structures of antiferromagnets and their functional nonlinearities for spintronics. While optical methods have been considered for…

Using a sensitive DC torque magnetometer we measure the orbital magnetization by sweeping the density at fixed magnetic fields on GaAs-AlGaAs heterostructures. At low temperatures strong nonequilibrium magnetization signals dominate the…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 D. R. Faulhaber , H. W. Jiang

Non-adiabatic contribution of environmental degrees of freedom yields effective inertia of spin in effective spin dynamics. In this paper, we study several aspects of the inertia of spin in metallic ferromagnets. (i) a concrete expression…

Mesoscale and Nanoscale Physics · Physics 2015-11-17 Toru Kikuchi , Gen Tatara

Laser-induced femtosecond magnetism or femtomagnetism simultaneously relies on two distinctive contributions: (a) the optical dipole interaction (ODI) between a laser field and a magnetic system and (b) the spin expectation value change…

Materials Science · Physics 2012-02-21 M. S. Si , G. P. Zhang

Magnetic field plays a crucial role in various novel phenomena in heavy-ion collisions. We solve the Maxwell equations numerically in a medium with time-dependent electric conductivity by using the Finite-Difference Time-Domain (FDTD)…

Nuclear Theory · Physics 2023-06-06 Hui Li , Xiao-Liang Xia , Xu-Guang Huang , Huan Zhong Huang

Efficient manipulation of magnetization at ultrashort time scales is of particular interest for future technology. Here, we numerically investigate the influence of the so-called field-derivative torque, which was derived earlier based on…

Materials Science · Physics 2019-10-02 Ritwik Mondal , Andreas Donges , Ulrike Ritzmann , Peter M. Oppeneer , Ulrich Nowak

Ultrafast laser pulses provide unique tools to manipulate magnetization dynamics at femtosecond timescales, where the interaction of the electric field -- such as excitation of spin carriers to non-equilibrium states, generation of…

We address the decoherence of a localized electron spin in an external magnetic field due to the hyperfine interaction with a lattice of nuclear spins. Using a completely non-perturbative method, rigorous bounds on the T_1 and T_2 coherence…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Neil Shenvi , Rogerio de Sousa , K. Birgitta Whaley

We present an ultrafast thermodynamics framework to model heat generation and entropy production in laser-driven ferromagnetic systems. By establishing a connection between the magnetic field strength of the laser pulse and magnetization…

Statistical Mechanics · Physics 2025-04-09 Finja Tietjen , R. Matthias Geilhufe

Understanding the nature of magnetic interactions in ultra-small magnetic ensembles and their intrinsic properties is vital to uncover the dynamics therein. In this study we reveal the spin dynamics of hexagonally arranged Fe atoms on…

Mesoscale and Nanoscale Physics · Physics 2018-08-21 Tamene R. Dasa , Valeri S. Stepanyuk

We develop a quantum analog of the classical spin-torque model for current-driven magnetic dynamics. The current-driven magnetic excitation at finite field becomes significantly incoherent. This excitation is described by an effective…

Materials Science · Physics 2009-11-10 S. Urazhdin

We draw attention on the fast oscillatory deviations from the residual non-ambipolarity in the case where electrons are driven by strong magnetic perturbations.

Plasma Physics · Physics 2009-11-07 F. Spineanu , M. Vlad

In spin-density-functional theory (SDFT) for noncollinear magnetic materials, the Kohn-Sham system features exchange-correlation (xc) scalar potentials and magnetic fields. The significance of the xc magnetic fields is not very well…

Strongly Correlated Electrons · Physics 2023-03-29 Daniel Hill , Justin Shotton , Carsten A. Ullrich

In this study, the temperature variations of the equilibrium and the non-equilibrium antiferromagnetic and ferromagnetic susceptibilities of a metamagnetic system are examined near the critical point. The kinetic equations describing the…

Statistical Mechanics · Physics 2015-05-28 Gul Gulpinar , Vatansever Erol