Ultrafast manipulation of magnetic anisotropy in a uniaxial intermetallic heterostructure TbCo2/FeCo. (1st February 2022)

• Record Type: Journal Article
• Authors: Ovcharenko, Sergei; Gaponov, Mikhail; Klimov, Alexey; Tiercelin, Nicolas; Pernod, Philippe; Mishina, Elena; Sigov, Alexander; Preobrazhensky, Vladimir
• Is Part Of: Journal of physics. Volume 55:Number 17(2022)
• Publication Date: 2022-02-01
• Subjects: ultrafast magnetization dynamics -- magnetic anisotropy -- spintronics -- pump-probe -- Landau–Lifschitz–Gilbert equation; Physics -- Periodicals; 530
• DOI: 10.1088/1361-6463/ac4a9a
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: We study experimentally and theoretically the dynamics of spin relaxation motion excited by a femtosecond pulse in the TbCo2 /FeCo multilayer structures with different ratios of TbCo2 to FeCo thicknesses r d = d T b C o 2 / d F e C o . The main attribute of the structure is in-plane magnetic anisotropy that is artificially induced during sputtering under a DC magnetic field. The optical pump-probe method revealed strongly damped high-frequency oscillations of the dynamical Kerr rotation angle, followed by its slow relaxation to the initial state. Modeling experimental results using the Landau–Lifshitz-Gilbert (LLG) equation showed that the observed entire dynamics is due to destruction and restoration of magnetic anisotropy rather than to demagnetization. For the pumping fluence of 7 mJ cm −2, the maximal photo-induced disruption of the anisotropy field is about 14% for the sample with r d = 1 and decreases when r d increases. The anisotropy relaxation is a three-stage process: the ultrafast one occurs within several picoseconds, and the slow one occurs on a nanosecond time scale. The Gilbert damping in the multilayers is found to be one order of magnitude higher than that in the constituent monolayers.