Spin-current-mediated rapid magnon localisation and coalescence after ultrafast optical pumping of ferrimagnetic alloys
Journal article, 2019
Sub-picosecond magnetisation manipulation via femtosecond optical pumping has attracted wide attention ever since its original discovery in 1996. However, the spatial evolution of the magnetisation is not yet well understood, in part due to the difficulty in experimentally probing such rapid dynamics. Here, we find evidence of a universal rapid magnetic order recovery in ferrimagnets with perpendicular magnetic anisotropy via nonlinear magnon processes. We identify magnon localisation and coalescence processes, whereby localised magnetic textures nucleate and subsequently interact and grow in accordance with a power law formalism. A hydrodynamic representation of the numerical simulations indicates that the appearance of noncollinear magnetisation via optical pumping establishes exchange-mediated spin currents with an equivalent 100% spin polarised charge current density of 10 7 A cm −2 . Such large spin currents precipitate rapid recovery of magnetic order after optical pumping. The magnon processes discussed here provide new insights for the stabilization of desired meta-stable states.
Author
Ezio Iacocca
National Institute of Standards and Technology (NIST)
Chalmers, Physics, Theoretical Physics
University of Colorado at Boulder
T. M. Liu
Stanford University
A. H. Reid
Stanford University
Z. Fu
Tongji University
S. Ruta
University of York
P. W. Granitzka
Stanford University
E. Jal
Stanford University
Stefano Bonetti
Stanford University
Stockholm University
Universita Ca' Foscari Venezia
A. X. Gray
Temple University
Stanford University
C. E. Graves
Stanford University
R. Kukreja
Stanford University
Z. Chen
Stanford University
D. J. Higley
Stanford University
T. Chase
Stanford University
L. Le Guyader
Stanford University
European XFEL
K. Hirsch
Stanford University
H. Ohldag
Stanford University
W. F. Schlotter
Stanford University
G. L. Dakovski
Stanford University
G. Coslovich
Stanford University
M. C. Hoffmann
Stanford University
Sebastian Carron
Stanford University
A. Tsukamoto
Nihon University
A. Kirilyuk
Radboud University
A. V. Kimel
Radboud University
Th Rasing
Radboud University
J. Stöhr
Stanford University
R. F.L. Evans
University of York
T. Ostler
Sheffield Hallam University
University of Liège
R. W. Chantrell
Radboud University
University of York
M. A. Hoefer
University of Colorado at Boulder
T. J. Silva
National Institute of Standards and Technology (NIST)
H. A. Dürr
Stanford University
Uppsala University
Nature Communications
2041-1723 (ISSN) 20411723 (eISSN)
Vol. 10 1 1756Subject Categories
Other Physics Topics
Condensed Matter Physics
DOI
10.1038/s41467-019-09577-0