Berlin 2015 – scientific programme

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MA: Fachverband Magnetismus

MA 29: Spincaloric Transport II (jointly with TT)

MA 29.1: Talk

Wednesday, March 18, 2015, 15:00–15:15, H 0110

Interface spin polarization in FM/Pt bilayers investigated by XRMR — •Christoph Klewe¹, Timo Kuschel¹, Jan-Michael Schmalhorst¹, Markus Meinert¹, Florian Bertram², Olga Schuckmann³, Joachim Wollschläger³, Matthias Opel⁴, Francesco Della Coletta⁴, Stephan Geprägs⁴, and Günter Reiss¹ — ¹CSMD, Physics Department, Bielefeld University, Germany — ²Division of Synchrotron Radiation Research, Lund University, Sweden — ³Physics Department, Osnabrück University, Germany — ⁴Walther-Meißner-Institut, BAdW, Garching, Germany

We demonstrate the suitability of x-ray resonant magnetic reflectivity (XRMR) for investigations of proximity induced interface spin polarizations. This technique was currently used to exclude magnetic proximity effects in NiFe₂O₄/Pt bilayers [1] in order to confirm the longitudinal spin Seebeck effect in this system, free from Nernst effects.

Here, we present photon energy dependent XRMR measurements (P09, PETRA III, DESY; ID12, ESRF) at the Pt L₃-absorption edge on Fe/Pt, and further investigations on the systems Ni_0.33Fe_0.66/Pt, Ni₈₀Fe₂₀/Pt, Ni/Pt, Fe₃O₄/Pt, and Y₃Fe₅O₁₂/Pt. A detailed analysis of the observed reflectivity curves based on varying magnetic profiles at the Pt interface and a comparison with ab initio calculations provides an accurate spatial distribution and quantitative values of the induced magnetic moments per Pt atom. We find a correlation of the Pt spin polarization and the Fe content of the adjacent ferromagnet, while we see no evidence for proximity effects in Y₃Fe₅O₁₂/Pt.

[1] T. Kuschel et al., submitted 2014, arxiv: 1411.0113