The 296th Special CMSM seminar 
Heavy Metal Proximity-Induced-Magnetism Effects on Spin Transport and Interlayer Coupling in Multilayers for Spintronics
Prof. Del Atkinson1,*
1 Department of Physics, Durham University, United Kingdom
* ICC Visiting Professor, Institute for Materials Research, Tohoku University
Date & Time: 14:00 - 15:00, January 8th (Thu), 2026.
Place: 2nd Conference Room, Main Bldg. 1F, Sengen.
Abstract:
Physical mechanisms occur at the interfaces between ferromagnetic (FM) and non-magnetic heavy metals (HM) in multilayered thin-film systems that are critical for spintronics. Heavy metals, in particular Pt, are of significant interest due to properties including large spin-orbit coupling and high spin Hall angle that are needed for spin-current generation and conversion [1], as well as the origin of PMA and interfacial DMI.
The Stoner criterion for Pt is close to the ferromagnet limit and it is well known that layering Pt with a ferromagnet (FM) induces magnetic polarization moments in Pt at the interface [2]. Proximity-Induced Magnetization (PIM), arises from d-d hybridization between Pt and FM atoms when layered, doped or alloyed [3]. Interfacial Pt PIM has been extensively studied and its role in spintronics has been explored, indicating it enhances the magnetoresistance ratio [4], reduces spin Hall effect efficiency [5], and increases magnetic damping in thin magnetic films via increased interfacial spin transport [6,7]. However, the linkage between different interfacial phenomena has been the subject of debate, including the role of proximity induced magnetisation (PIM) in spin transport across FM/HM interfaces. Furthermore, PIM has been proposed to play a potential role as a pathway for mediating interlayer coupling through Pt [8]. However, while Pt PIM is proposed to induce interlayer FM coupling within FM/Pt/FM systems, neither experimental nor theoretical evidence have conclusively supported this hypothesis.
In the first part of this seminar, PIM is introduced in heavy metals layered with ferro- and ferri-magnetic materials [9,10]. Spin transport across FM/HM interfaces is then discussed and our recent work demonstrating the relationship between PIM and spin transport is presented [6, 7]. This includes element specific X-ray magnetic circular dichroism (XMCD) and spin-pumping from ferromagnetic resonance measurements on the same CoFe/Au/Pt and NiFe/Au/Pt samples. Results show a strong relationship between the magnitude of Pt PIM and the spin-pumped enhancement of damping and hence the interfacial spin transport.
The second part addresses the research around the role of PIM in interlayer coupling in FM/Pt/FM systems. Using XMCD and X-ray Resonant Magnetic Reflectivity (XRMR) measurments and MOKE, we show that FM interlayer coupling arising when two FM/Pt interfaces are brought together, indicating that the resulting continuous Pt PIM enables ferromagnetic interlayer coupling between FM layers through the Pt [11].
References
[1] Wang, Lei, et al. Physical Review Letters 116.19 (2016): 196602.
[2]Herrmannsdörfer, T., et al. J. of Low Temperature Physics 104 (1996): 49-65
[3] Lim, W. L., et al. (2013). Applied Physics Letters, 102 (16), 162404.
[4] Zhou, X., et al. Physical Review B 92.6 (2015): 060402.
[5] Zhang, Wei, et al. Physical Review B 91.11 (2015): 115316.
[6] Swindells, C., et al.& D. Atkinson Applied Physics Letters 119.15 (2021).
[7] Swindells, C., et al. & D. Atkinson Physical Review B 105, 094433 (2022).
[8] Omelchenko, et al. (2018). Applied Physics Letters, 113(14), 142401.
[9] Rowan-Robinson R.M., et al. & D. Atkinson Scientific reports 7 (1), 16835 (2017)
[10] Swindells, C., et al. & D Atkinson Physical Review Research 2 (3), 033280 (2020)
[11] Rianto, D., et al. & D. Atkinson “Proximity-Induced-Magnetization in Interlayer Coupling in Ferromagnetic/Heavy Metal/Ferromagnetic Multilayers” - Submitted (2026)
(Contact)
Yuya Sakuraba
Group Leader, Magnetic Functional Device Group,
Research Center for Magnetic and Spintronic Materials (CMSM)
E-mail:
SAKURABA.Yuya[at]nims.go.jp
