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MA: Fachverband Magnetismus

MA 35: Magnetization / Demagnetization Dynamics II

MA 35.12: Talk

Wednesday, March 18, 2015, 18:00–18:15, EB 301

Ultrafast demagnetization dynamics in Ni/Ru/FePt/MgO(100) films — •Sadashivaiah Sakshath¹, Oliver Schmitt¹, Moritz Barkowski¹, Patrick Matthes², Manfred Albrecht^2,3, Mirko Cinchetti¹, Stefan Mathias¹, and Martin Aeschlimann¹ — ¹Technische Universität Kaiserslautern, Germany — ²Technische Universität Chemnitz, Germany — ³Universität Augsburg, Germany

Non-collinear magnetic layers allow us to study the influence of one ferromagnetic layer on the ultrafast dynamics of the non-collinear ferromagnet, primarily due to a spin current through the spacer layer [1,2]. We follow the dynamics of the in-plane magnetized Ni layer, as influenced by the perpendicularly magnetized FePt, using Ni/Ru/FePt/MgO(100) films. By changing the thickness of the Ru layer, we tune the amount of spin currents flowing between the magnetic layers [3]. When the thickness of Ru is low, Ni is observed to demagnetize faster in the non-collinear than in the collinear configuration. At high Ru thickness, the rate of demagnetization is the identical in both configurations, since the ultrafast spin currents do not reach the Ni layer. Additionally, at high Ru thickness, the observed magneto-optic signal shows a transient change of sign.

[1] A. J. Schellekens et al., Nat. Comm. 5, 4333 (2014)

[2] G-M. Choi et al., Nat. Comm. 5, 4334 (2014)

[3] E. Turgut et al., Phys. Rev. Lett. 110, 197201 (2013)