Dresden 2017 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

MA: Fachverband Magnetismus

MA 23: Spin Dynamics and Transport: Ultrafast Effect

MA 23.3: Vortrag

Dienstag, 21. März 2017, 10:00–10:15, HSZ 403

Ultrafast excitation of coherent magnons by circularly and linearly polarized light pulses in antiferromagnetic NiO — •Christian Tzschaschel¹, Ryugo Iida², Tsutomu Shimura², Hiroaki Ueda³, Stefan Günther¹, Takuya Satoh^2,4, and Manfred Fiebig¹ — ¹ETH Zürich, Switzerland — ²The University of Tokyo, Japan — ³Kyoto University, Japan — ⁴Kyushu University, Japan

NiO is rapidly gaining importance in the field of antiferromagnetic magnonics. In this talk, we clarify the mechanism of ultrafast optical magnon excitation in antiferromagnetic NiO. We employed time-resolved optical two-color pump-probe measurements to study the coherent non-thermal spin dynamics. By near-infrared pumping and probing along the optical axis, we avoid the detrimental influence of birefringence. Thus, we are able to determine the mechanism behind the ultrafast optical magnon generation with linearly and circularly polarized light. For this purpose, we employ a phenomenological theory under consideration of the crystallographic and magnetic point group symmetries. Based on this new approach, we are able to describe the dynamic magneto-optical properties of NiO and derive expressions for the optically induced magnetization via the inverse Faraday effect as well as the inverse Cotton-Mouton effect. Our experimental and theoretical results are in striking agreement. This not only allows us to discriminate between the two effects, but also to extract information about the antiferromagnetic domain distribution. Moreover, we find that magnon generation via the inverse Cotton-Mouton effect is more than 30 times more efficient in NiO than via the inverse Faraday effect.