Acquisition of a Superconducting Magnetooptical Cryostat for Research and Student Training in Magnetoelectronic Materials

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This is an award from the Instrumentation for Materials Research program in DMR to the College and William and Mary. The award is for acquisition of a 7 Tesla superconducting magnetooptical cryostat for the study of nonlinear magnetooptical effects and magnetotransport 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. This equipment will be incorporated into a system for 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. The instrument will also be used in training of students at the College to study materials important for magnetoelectronics. %%%This award from the Instruments for Materials Research to the College of William and Mary is for the acquisition of a low-temperature, high-field magnetooptical cryostat which will enhance research and education in the areas of magnetooptics and magnetotransport at the College. The cryostat will be incorporated into a system which uses ultrafast pulsed laser techniques (with laser pulses less than one-trillionth of a second in duration) 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").