Elemental asymmetries of spin and electron dynamics in an insulating ferrimagnet
Journal article, 2025
NiFe2O4 has gained significant attention from the scientific community due to its potential applications in microwave integrated devices, magnetoelectric coupling heterostructures, and spintronic devices such as spin filters. In this work, we explore the element specific ultrafast dynamics of NiFe2O4 films grown on ZnGa2O4 and MgAl2O4 with different lattice mismatches. To examine the dynamics, we utilize the transverse magneto optical Kerr effect at the extreme ultraviolet (XUV) regime, which provides access to the Fe and Ni M-edges. The demagnetization is almost concurrent with the pump pulse, suggesting that slower phonon based interactions are not crucial for the demagnetization. The reflectivity of the MAO sample is significantly higher than for the ZGO sample, which correlates well with the increased amount of free carriers. Furthermore, the reflectivity exhibits pronounced oscillations in both the Fe and Ni signals with a period of ∼ 2.8 ps (0.36THz). Notably, the onset of the oscillations of the Fe is delayed by about 0.2–0.5ps with respect to the Ni.
Author
S. Saha
Ashoka University
R. Knut
Uppsala University
R. S. Malik
Uppsala University
Kasturie Dileep Jatkar
Chalmers, Microtechnology and Nanoscience (MC2), Terahertz and Millimetre Wave Laboratory
Uppsala University
Robert Stefanuik
Uppsala University
Somnath Jana
Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy
Uppsala University
J. Söderström
Uppsala University
A. Gupta
University of Alabama
F. Radu
Helmholtz Association of German Research Centres
C. Luo
Technical University of Munich
Helmholtz Association of German Research Centres
Olof Karis
Uppsala University
D. A. Arena
University of South Florida
Applied Physics Letters
0003-6951 (ISSN) 1077-3118 (eISSN)
Vol. 127 22 222406Subject Categories (SSIF 2025)
Atom and Molecular Physics and Optics
Condensed Matter Physics
DOI
10.1063/5.0285087