New insights into the origin of magnetic anisotropy and damping by use of broadband ferromagnetic resonance spectroscopy
Justin M. Shaw
Physicist at National Institute of Standards and Technology, Boulder, CO, USA
The ability to control perpendicular magnetic anisotropy and damping in thin film magnetic materials is critical for many current and future technologies in data storage and spintronics. For example, materials with high perpendicular anisotropy provide the required thermal stability in data storage and magnetic random access memory (MRAM) as the dimensions of “bits” or devices are scaled below 25 nm. At the same time, the energy required to reverse a device must be reduced, which correspondingly requires a smaller damping parameter to compensate for the higher anisotropy. The damping parameter also strongly affects the maximum rate at which a switching event can be achieved. Despite the importance of anisotropy and damping to data storage and spintronics, the fundamental origin, as well as a quantitative description, of these two phenomena remains controversial. For example, in recent years there has been significant debate about a possible relationship between perpendicular anisotropy and the damping parameter. Such a relationship would have a negative impact on the discussed technologies since scaling requires a simultaneous increase in anisotropy and lower damping.
The speaker will present an overview of their latest work to increase the sensitivity and precision of broadband ferromagnetic resonance spectroscopy measurements. With these improved methods, detailed information about the structure of the orbital momentum, damping, anisotropy and inhomogeneity of the material can be discerned. We then apply these techniques to study the origin of perpendicular magnetic anisotropy and damping in several thin film systems. Finally, Justin will also directly address the controversy of a possible link between perpendicular anisotropy and damping, and provide framework by which these two quantities can be separately engineered.
Justin M. Shaw is a Physicist at National Institute of Standards and Technology, Boulder, CO, USA
|Venue||Kinesis, Level 7, Seminar Room 3.
4 Fusionopolis Way, Singapore 138635
|Date||09 Dec 2015
|Time||10am - 12pm
|Registration at||9.30am (Walk-in participants to register on-site)
|Please confirm your attendance by
||09 Dec 2015