Magnetic tunnel junctions for memory and dynamics applications
Speaker: Dr hab. Witold Skowroński, Prof. AGH AGH University of Krakow, Institute of Electronics
Date, time: October 22, 2025 , 13:00 – 14:00
Abstract: Magnetic tunnel junction (MTJ) – a simple trilayer structure, consisting of two thin ferromagnets separated by even thinned tunnel barrier, allowing for electrons to tunnel and preserve the spin orientation – is a fundamental building block of modern spintronic devices. It has been successfully applied in storage (hard disc drives, magnetic random access memories) and sensing (magnetic field sensors) applications [1]. Further optimization is anticipated, so that MTJs can be used beyond conventional magnetic components, such as high-frequency electronic components or building blocks of unconventional computing platforms. In the talk, I will introduce the modern MTJ structure, challenges and outlook for further optimization including material structure, control mechanism and scaling. I will mention recent activities related to the reduction of less-abundant material usage [2], and utilization of so-called spin-orbit torque (SOT), which enables fast (and therefore energy-efficient) writing [3]. Then I will move on to the discussion of the magnetization dynamics in MTJ. Magnetization precession induced by radio-frequency voltage application enables determination of the influence on the electric field on the magnetic anisotropy also in a GHz frequency range [4]. Upon application of the DC current in the optimized structure one ca also obtain a stable magnetization precession, which can be further stabilized using the magnetic feedback loop [5]. Finally, I will discuss the possibilities of MTJ utilization in novel unconventional computing platforms, which includes neural networks [6] and reservoir computing [7], which is envisioned to contribute to the development of dedicated artificial intelligence hardware with more energy-efficient computation.
Acknowledgments: The author acknowledges grant Sheng no. 2021/40/Q/ST5/00209 from the National Science Centre, Poland and the Excellence initiative-research university (IDUB) programme of the AGH University of Krakow.
References:
[1] – B. Dieny et al. Nature Electron. 3, 446 (2020)
[2] – M. Cierpiał et al. Scientific Reports 15, 35227 (2025)
[3] – L. Liu et al Phys. Rev. Lett. 106, 036601 (2011)
[4] – W. Skowroński et al. Appl. Phys. Lett. 115, 072401 (2019)
[5] – W. Skowroński et al. Scientific Reports 9, 19091 (2019)
[6] – P. Rzeszut et al. Scientific Reports 12, 7178 (2022)
[7] – C. Heins et al. arxiv 2509.19483 (2025)
Chairman: Aleksandra Trzaskowska
https://mtpr.amu.edu.pl/event/magnetic-tunnel-junctions-for-memory-and-dynamics-applications/