DMG Seminar - Wednesday 5 June - SAMER KURDI

Antiferromagnetic Spintronics

"Antiferromagnetic Spintronics: An Unexpected Journey"

talk by

Samer Kurdi

at 1:15 pm in Goldsmiths 1.

{Duration ~ 25 minutes}

ABSTRACT

Antiferromagnetic Spintronics: An Unexpected Journey

Samer Kurdi¹, Philipp Zilske², Yuya Sakuraba³, Xiandong Xu³, Zoe H. Barber¹, Günter Reiss², Jungwoo Koo^2
1 Device Materials Group, Department of Materials Science and Metallurgy, University of Cambridge, UK
² Physics Department, Center for Spinelectronic Materials and Devices, Bielefeld University, Germany
³ Research Center for Magnetic and Spintronic Materials, National Institute for Materials Science (NIMS), Japan

Spin electronics (spintronics) has recently gained much traction to overcome the challenge of continued miniaturization of memory devices. Antiferromagnetic materials (AFMs) offer higher stability than ferromagnetic-based devices, with high packing density due to minimal stray fields and insensitivity to external magnetic fields. Such insensitivity is crucial to make “invisible” memories for encryption and safe data storage to meet demands in current information technologies. Proof of concept of such memory devices has been shown by electrically induced switching^1,2.

In this work we study the non-collinear D0₁₉ ε-Mn₃X (X = Ga, Sn) AFM systems. To date such compounds have only been studied as single crystal bulk samples^3-6, and it is essential to be able to deposit them as thin films, with precisely controlled structure and crystallography, for future device applications. Vapour deposition and optimization of thin film structures are described, using magnetron sputtering at the University of Bielefeld, Germany. Here we explain the growth of Mn₃X thin films on an optimized Ru-buffer deposited on c-plane sapphire substrates. Detailed structural characterization has been performed with High Resolution X-Ray Diffraction and Atomic Force Microscopy and Transmission Electron Microscopy. High quality epitaxy has been achieved and growth parameters have been optimized for several compositions. Magnetic characterization on the optimized thin films will also be introduced and the difficulties of measuring their very small moments (~0.002 μ_B/Mn) will be mentioned. Preliminary transport measurements that were considered as forbidden effects in AFMs  (anomalous Hall and Nernst effects), will be discussed briefly and the next steps on optimizing their properties considered.

At the end, I will speak about how my journey to Tsukuba Japan to work on this project took place and I will give you insight on how current PhD students can also potentially work at the Japanese National Institute for Materials Science as part of their PhD training.

[1]     P. Wadley et al., Science 351, 587-590 (2016).
[2]    K. Olejník et al., Nature Communications. 8, 1 – 7 (2017).
[3]     A.K. Nayak. et al., Science. 2, 1-5 (2016).
[4]     S. Nakatsuji et al., Nature. 527, 212 (2015).
[5]     M. Ikhlas et al., Nature Physics. 13, 1085 - 1091 (2017).
[6]     M. Kimata et al., Nature. 565, 627–630 (2019)