Lecture A.V. Kimel
|16 februari 2004||FWN-Building 5116.0116, Nijenborgh 4, 9747 AG, Groningen|
|Speaker:||Dr. A.V. Kimel|
|Affiliation:||NSRIM Institute, University of Nijmegen|
|Title:||Ultrafast manipulation of spins in antiferromagnetic materials|
|Date:||Mon Feb 16, 2004|
|Host:||P.H.M. van Loosdrecht|
|Telephone:||+31 50 363 8149|
The study of ultrafast magnetization dynamics has become one of the hottest topics in condensed- matter physics, stimulated on the one hand by the demands of the ever increasing speed to write and retrieve magnetically stored information, and on the other, by the development of ultrafast (femtosecond) laser sources. The latter are able to excite a medium at much shorter time scales than fundamental quantities such as spin precession or spin-lattice relaxation times. So far, most studies of ultrafast spin dynamics were focused on ferromagnetic materials because of their obvious relevance for applications. However, due to the fact that in antiferromagnets, no angular momentum is associated with the order parameter, spin dynamics in these materials is intrinsically much faster than in ferromagnets.
Here we report on the quenching of antiferromagnetic order in iron borate FeBO3, induced by ultrafast laser excitation . This experiment has allowed us to reveal “bottlenecks” that affect the dynamics of the photo-induced manipulation magnetic state of a medium and develop novel approach for ultrafast manipulation antiferromagnetic spins. We demonstrate an efficiency of this new approach and show that, using a short laser pulse, the spins of antiferromagnetic TmFeO3 can indeed be manipulated on a time scale of a few picoseconds, in contrast to the hundreds of picoseconds in a ferromagnet [2,3]. This observation demonstrates that antiferromagnetic materials posses a huge potential for truly ultrafast magnetic memory.
 A. V. Kimel, R. V. Pisarev, J. Hohlfeld, and Th. Rasing, Phys. Rev. Lett. 89, 287401 (2002)
 Th. Gerrits, H. A. M. van den Berg, J. Hohlfeld, L. Bär, and Th. Rasing, Nature 418, 509 (2002)
 H. W. Schumacher, C. Chappert, P. Crozat, R. C. Sousa, P. P. Freitas, J. Miltat, J. Fassbender, and B. Hillebrands, Phys. Rev. Lett. 90, 017201 (2003)
|Laatst gewijzigd:||22 oktober 2012 14:30|