Spin-current mediated exchange coupling in MgO-based magnetic tunnel junctions

DOI: 10.1103/PhysRevB.103.064416

Authors: L. Gladczuk (University of Oxford; Diamond Light Source) , L. Gladczuk (Institute of Physics, Polish Academy of Science) , P. Dluzewski (Institute of Physics, Polish Academy of Science) , K. Lasek (Institute of Physics, Polish Academy of Science) , P. Aleshkevych (Institute of Physics, Polish Academy of Science) , D. M. Burn (Diamond Light Source) , G. Van Der Laan (Diamond Light Source) , T. Hesjedal (University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Physical Review B , VOL 103

State: Published (Approved)
Published: February 2021
Diamond Proposal Number(s): 21616 , 18759

Abstract: Heterostructures composed of ferromagnetic layers that are mutually interacting through a nonmagnetic spacer are at the core of magnetic sensor and memory devices. In the present study, layer-resolved ferromagnetic resonance was used to investigate the coupling between the magnetic layers of a Co/MgO/Permalloy magnetic tunnel junction. Two magnetic resonance peaks were observed for both magnetic layers, as probed at the Co and Ni L 3 x-ray absorption edges, showing a strong interlayer interaction through the insulating MgO barrier. A theoretical model based on the Landau-Lifshitz-Gilbert-Slonczewski equation was developed, including exchange coupling and spin pumping between the magnetic layers. Fits to the experimental data were carried out, both with and without a spin pumping term, and the goodness of the fit was compared using a likelihood ratio test. This rigorous statistical approach provides an unambiguous proof of the existence of interlayer coupling mediated by spin pumping.

Journal Keywords: Magnetic tunnel junctions; Multilayer thin films; Ferromagnetic resonance; X-ray magnetic circular dichroism

Subject Areas: Materials, Physics


Instruments: I10-Beamline for Advanced Dichroism

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