CAREER: Nonlinear Optical Studies of Spin and Magnetization Dynamics in Ferromagnetic Multilayers

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This Faculty Early Career Development (CAREER) project seeks to enhance research and education in the areas of modern optics and condensed matter physics at the College of William and Mary. The objective in research is to apply the newest techniques in ultrafast pump-probe laser spectroscopy, including frequency-dependent and time-resolved magneto-optical Kerr effect and magnetization-induced second harmonic generation, to answer questions regarding spin polarization and spin and magnetization dynamics in ferromagnetic thin film multilayers. Such multilayers are showing great promise in technological applications, but are limited by incomplete knowledge of electron spin lifetimes and the sources of spin scattering and spin-flipping. Systems to be explored include magnetic multilayers displaying giant magnetoresistance, half-metallic materials and metal/semiconducting systems. This work will continue to develop non-destructive, fast and straightforward nonlinear optical techniques to measure parameters crucial for spin-based devices. The educational goal of this project is the development of a series of laboratory modules which will be used to introduce modern optics and the physics of materials to undergraduates at the College as well as be used in outreach programs to the local community.%%%This Faculty Early Career Development (CAREER) project seeks to enhance research and education in the areas of modern optics and the physics of materials at the College of William and Mary. In research, ultrafast pulsed laser techniques (with laser pulses less than one-trillionth of a second in duration), will be used to measure how the magnetic properties of thin-film ferromagnetic multilayers evolve in time. In these techniques, a "pump" beam is used to excite the material under study while a second pulsed beam "probes" or takes a snapshot of the state of the system later in time. Such techniques have been successfully used, for example, to study chemical reactions as they occur, and have only recently been applied to magnetic materials. The study of the ultimate speed of magnetic processes and what determines the magnetic and electrical properties of magnetic thin films is extremely important for the design of electronic and magnetic devices such as hard drive read heads, nonvolatile computer memory and the next generation computer devices based on electron spin (dubbed "Spintronics" or Magnetoelectronics"). The educational goal of this project is the development of a series of hands-on laboratory modules which will be used to introduce modern optics and the physics of materials to undergraduates at the College as well as be used in outreach programs to the local community.***