Emerging hard disk drive (bit-patterned media, energy assisted magnetic recording) and spintronics (spin-RAM, spin-torque oscillators) technologies require novel materials that have ever-increasing demands on fabrication compatibility and performance. One of these demands is for materials that combine both high perpendicular anisotropy (i.e., remanent magnetization lies out of the film plane) and low damping (i.e., the coupling between spins and the relevant thermal reservoir). However, the fundamental origins of perpendicular anisotropy and their effect on magnetization dynamics are not well understood. We seek to determine the fundamental origins of perpendicular anisotropy in a variety of technologically relevant materials. In addition, we seek to determine how anisotropy affects magnetodynamic properties. In particular, we wish to determine the adjustable parameters that determine the damping. Previous work by us and others has shown that the dynamic properties of these materials can change substantially as a result of spatial confinement when patterned into nanostructures.

In order to study the magnetization of such structures, we are developing new measurement techniques to study both quasi-static and dynamic magnetization processes, with the intention to use these new techniques to correlate the magnetodynamic properties with the fundamental material microstructure (e.g., crystallinity, orientation, roughness, and precise composition). Available dynamic measurement instrumentation includes a 70 GHz broadband ferromagnetic resonance spectrometer, a novel broadband magneto-optic Kerr effect-based microscope, and Brillouin light scattering. Material characterization is performed with x-ray diffraction, electron microscopy, and atomic force microscopy. Materials and samples are fabricated with state-of-the-art deposition tools and a recently commissioned 18,000 ft2 Class-100 cleanroom with both optical and e-beam lithography facilities.

 

key words

Damping; Spin-dynamics; Perpendicular anisotropy; Ultrafast; Magnetic materials; Spintronics; Nanomagnetics; Ferromagnetic resonance; Magnetodynamics;

Citizenship:  Open to U.S. citizens

Level:  Open to Postdoctoral applicants