Friday, October 6, 2006, 10:30 am — Seminar Room, Bldg. 725
Ferromagnetic moments M precess (spiral) around applied fields H, at GHz frequencies, until they are aligned by relaxation. Although ferromagnetic relaxation is formally similar to electrical resistivity, and its materials engineering is crucial for the high-data-rate performance of spin electronic devices, its origins and best paths for control are somewhat obscure. I describe our development of stroboscopic, element-specific magnetization dynamics measurements, through time-resolved x-ray magnetic circular dichroism (tr-XMCD) in transmission, to "see inside" the relaxation process. Phase lags between spin and orbital moments in an element, elemental moments in an alloy, and layer moments in a heterostructure are all proposed as signatures of relaxation mechanisms, and can be observed using tr-XMCD. We have demonstrated temporal resolutions in the few-picosecond range, three orders of magnitude faster than have been achieved previously, in measurements of alloys and bilayers at the Advanced Photon Source. I will discuss the opportunities for measurements with improved (femtosecond) time resolution at new facilities such as NSLS-II.
Joint work with D.A. Arena, E. Vescovo, and C.-C. Kao, NSLS.
Hosted by: Dario Arena
3222 | INT/EXT | Events Calendar
Not all computers/devices will add this event to your calendar automatically.
A calendar event file named "calendar.ics" will be placed in your downloads location. Depending on how your device/computer is configured, you may have to locate this file and double click on it to add the event to your calendar.
Event dates, times, and locations are subject to change. Event details will not be updated automatically once you add this event to your own calendar. Check the Lab's Events Calendar to ensure that you have the latest event information.