研究目的
To develop an advanced micromagnetic solver for the numerical study of all-optical switching (AOS) processes, aiming to provide a theoretical description of helicity-dependent magnetization switching in ferromagnetic systems using laser pulses.
研究成果
The developed micromagnetic model successfully describes helicity-dependent all-optical switching in ferromagnetic thin films, showing good agreement with experimental results. It explains the fluence threshold for switching and the expansion of inverted domains with multiple pulses. The model provides a foundation for understanding AOS physics and can be extended to include other mechanisms or applied to different magnetic systems.
研究不足
The model assumes the inverse Faraday effect is the dominant helicity-dependent mechanism, but other effects like magnetic circular dichroism or laser-induced spin currents are not included. The simulations are computationally intensive due to small time steps and large sample sizes. The study is limited to ferromagnetic thin films with high perpendicular anisotropy and may not generalize to other materials or systems.
1：Experimental Design and Method Selection:
The study employs a numerical micromagnetic model based on the Landau-Lifshitz-Bloch (LLB) equation coupled with the three-temperature model (3TM) to simulate the dynamics of magnetization under laser pulses. The model includes various interactions such as exchange, anisotropy, Dzyaloshinskii-Moriya interaction, and a magnetooptical effective field from the inverse Faraday effect (IFE).
2：Sample Selection and Data Sources:
The simulations use parameters typical for a Pt/Co bilayer thin film with high perpendicular magnetic anisotropy, including saturation magnetization, anisotropy constant, Curie temperature, damping factor, exchange stiffness, DMI constant, thermal conductivities, and coupling constants. Disorder is modeled with grain variations.
3：List of Experimental Equipment and Materials:
No specific physical equipment is mentioned; the study is computational, using a custom-developed micromagnetic solver. Materials include ferromagnetic thin films like Pt/Co bilayers.
4：Experimental Procedures and Operational Workflow:
The model simulates the application of circularly polarized laser pulses with Gaussian spatial and temporal profiles to the sample. The LLB equation is solved numerically to track magnetization dynamics, coupled with the 3TM for temperature evolution. Stochastic thermal noise is included, and simulations are run for multiple laser pulses to observe switching behavior.
5：Data Analysis Methods:
Results are analyzed through snapshots of magnetization evolution, average magnetization values, and temperature profiles. Comparisons are made with experimental observations to validate the model.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
