TY  - JOUR
A1  - Deb, Marwan
A1  - Molho, Pierre
A1  - Barbara, Bernard
T1  - Magnetic damping of ferromagnetic and exchange resonance modes in a ferrimagnetic insulator
JF  - Physical review : B, Condensed matter and materials physics
N2  - Understanding the damping is an important fundamental problem with widespread implications in magnetic technology. Ferrimagnetic materials offer a rich platform to explore not only the damping of the ferromagnetic mode, but also the damping of the high-frequency exchange mode very promising for ultrafast devices. Here we use time-resolved magneto-optical Kerr effect to investigate the ferromagnetic and exchange resonance modes and their damping in the bismuth-doped gadolinium iron garnet over a broad range of magnetic fields (0-10 T) and temperatures (50-300 K) including the magnetization and angular compensation points. These two resonance modes are excited via the inverse Faraday effect and unambiguously identified by their distinct frequency dependence on temperature and magnetic field. The temperature-dependent measurements in the external magnetic field H-ext = 2 T revealed that the intrinsic damping of the ferromagnetic mode is always smaller than the one of the exchange modes and both have a maximum near the angular compensation point. These results are fully consistent with recent predictions of atomistic simulations and a theory based on two-sublattice Landau-Lifshitz-Bloch equation. We also demonstrate that the damping of these modes varies differently as a function of H-ext. We explain the observed behaviors by considering the different features of the effective fields defining the precession frequencies of the ferromagnetic and exchange modes.
Y1  - 2022
U6  - https://doi.org/10.1103/PhysRevB.105.014432
SN  - 2469-9950
SN  - 2469-9969
VL  - 105
IS  - 1
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Deb, Marwan
A1  - Molho, Pierre
A1  - Barbara, Bernard
T1  - Tunable exchange-bias-like effect in bi-substituted Gadolinium iron garnet film
JF  - Physical review applied
N2  - Using magneto-optical Faraday and Kerr measurements, we investigate the magnetic and magnetooptical properties of a thick Bi-substituted gadolinium iron garnet film over a broad range of wavelengths (250-850 nm) and temperatures (150-300 K), including the magnetization compensation point, TM. We observe an exchange-bias-like effect in the vicinity of TM. By slightly changing the sample temperature, we can precisely tune the bias field, which reaches a magnitude 6 times higher than the coercive field. We explain this phenomenon by considering the short-range superexchange interaction and a change in the magnetic behavior when moving from the surface to the bulk of the film. This finding may lead to the development of single-film magneto-optical devices based on the exchange-bias effect.
Y1  - 2021
U6  - https://doi.org/10.1103/PhysRevApplied.15.054064
SN  - 2331-7019
VL  - 15
IS  - 5
PB  - American Physical Society
CY  - College Park
ER  -