Spin current effects in nanostructured films

• Applicant: Professor Dr. Markus Münzenberg
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2004 to 2009
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5430695

Focus of the project will be spin current effects in patterned magnetic structures. We propose to investigate the eigen modes of magnetic excitations depending on the shape of the structures. In how far can special modes be selected and manipulated in an all optical pump and probe experiment using a Ti:sapphire laser pulse as a stroboscopic flashlight? The exciting pump pulse generates a nonequilibrium situation. Scattering processes during the relaxation process result in a coupling of the spin system with the thermalizing electron system as described in the three temperature model, and triggers coherent and non coherent magnetization dynamics. Rather small demagnetization effects of ~5-10% excite fundamental modes of the spin system as we have seen in micromagnetic simulations. The modes are strongly dominated by dipolar fields. Focus of this project will be the study of spin currents evolving from this nonequilibrium situation at the interfaces of layered systems. Spin current effects enter in the complex dynamics of the spin ensemble in two ways: Firstly, the coherent precession of a spin system excites a spin current in an adjacent nonmagnetic metallic layer. This acts as an additional damping dependent on the spin orbit scattering. Secondly, spin currents injected into a magnetic structure start a precession of the spin system by conserving the total angular momentum. Both effects will be studied within the proposed project.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1133: Ultrafast magnetization processes