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

Journal article

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 L3 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.

Authors: Gladczuk, L; Gladczuk, L; Dluzewski, P; Lasek, K; Aleshkevych, P

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Physical Society
• Journal: Physical Review B: Condensed Matter and Materials Physics
• Volume: 103
• Issue: 6
• Article number: 064416
• Publication date: 2021-02-09
• Acceptance date: 2021-01-27
• DOI: 10.1103/PhysRevB.103.064416
• EISSN: 1550-235X
• ISSN: 1098-0121
• Language: English
• Keywords: FFR