Magnetization dynamics induced by ultrashort terahertz radiation: Toward designing spin-based terahertz sensors

Abstract

A convenient analytical description of an ultrashort terahertz pulse and an analysis of the influence of this pulse on the Zeeman torque dynamics are extremely important tasks due to the potential applications of terahertz radiation. The theoretical expressions proposed in this paper clarify the physics of magnetic dynamics under the action of the magnetic field of a terahertz pulse and show the role of individual parameters of the material and the pulse field in this process. On the basis of the formulas obtained and the available experimental data for fcc-Co film, we analyze the possibilities of recovering information about the magnetic field of the pulse from the observation of magnetization dynamics, as well as the effect of fluence, Gilbert damping, and magnetic anisotropy on the magnetization dynamics induced by ultrashort terahertz radiation. The theoretical framework presented could potentially be used in the design and optimization of a new generation of terahertz detectors based on the magnetic component of the electromagnetic field.