Regensburg 2013 – scientific programme
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DS: Fachverband Dünne Schichten
DS 25: Focus Session: Magnetic Damping Phenomena in Thin Films and Nanostructures (jointly with MA)
DS 25.2: Topical Talk
Wednesday, March 13, 2013, 15:30–16:00, H10
Magnetic Damping on Femtosecond Time Scales — •Markus Münzenberg — Georg-August University, I. Phys. Institute, Göttingen, Germany
Achieving high speed magnetization dynamics in magnetic materials is at the heart of the engineering of spin-based electronic devices. Microscopic processes in a magnetic materials involve electrons, their spins, and their interactions with phonons. Materials with low damping constants can be realized by controlling the spin-flip channels at the Fermi level. Metallic Heusler compounds show a Gilbert damping of 0.002-0.006, however, the theoretically predicted values are 10−5−10−4.
The experiments we report in this talk demonstrate a successful control of spin polarization and spin dynamics on ultrafast time scales in magnetic materials through their electronic structure. For achieving a systematic variation in their electronic structure as a control, we have made a selection of so-called half-metals, in the family of the Heusler compounds and pseudogap materials that are close relatives, but their electronic structure is robust against structural disorder. Interestingly, similar values of spin polarization are seen in the pseudogap materials as well, making them another promising class of high-spin-polarization materials.
[1] A. Mann, J. Walowski, M. Münzenberg, S. Maat, M. J. Carey, J. R. Childress, C. Mewes, D. Ebke, V. Drewello, G. Reiss, A. Thomas, Phys. Rev. X 2, 041008 (2012).