Spintronic phenomena and devices

Supervisor: Prof. Dr. Stuart Parkin
Responsible Scientific Pillar Coordinator: Dr. Jae-Chun Jeon

A state-of-art racetrack memory application - where we use spin-dependent phenomena such as spin orbit torque and spin-polarized electron tunneling.

A state-of-art racetrack memory application - where we use spin-dependent phenomena such as spin orbit torque and spin-polarized electron tunneling.

Spintronics deals with manipulation, generation, detection of spin-polarized electrons in a wide variety of materials and devices. We explore from fundamentals (spin Hall effect, spin orbit torque, exchange torque, etc.) to sophisticated material science (atomically engineered materials, chiral antiferromagnetic materials, novel alloys) and cutting-edge devices (racetrack, magnetic tunnel junction, neuromorphic devices) for applications. As scaling-down of CMOS-based devices gets slower, radical solutions are necessary in order to fulfill the demands for processing the rapidly growing amount of data. Spintronics is one of the most promising candidates since spintronic devices can offer faster, reliable, high density, and energetically efficient solutions for next-generation computation technologies.

We explore novel physics and spin-dependent phenomena from atomically engineered spintronic materials and state-of-the-art devices. Our primary goal is to explore and find novel properties and physics from spintronic materials and devices that are energetically and functionally superior compared to charge-based systems.

For spintronics research, we prepare and investigate atomically engineered ultra-thin films, novel alloys, and combination of multiple deposition techniques using our home-built multi-source deposition system (see picture) where DC/RF sputtering, molecular beam epitaxy (MBE), e-beam evaporation, pulsed laser deposition, and 2D material exfoliation chambers are connected via an ultra-high vacuum tube system.

For device applications, we explore most creative spintronic devices and systems. In particular, we aim to develop energy-efficient spintronic devices (spin orbit torque switching devices with variety of materials, such as 2D materials, complex alloys [1], chiral antiferromagnets [2, 3], atomically engineered thin films [4]), and chiral domain wall based devices, so called ‘Racetrack’ [5 – 7], for in-memory, neuromorphic, and probabilistic computing technologies. Furthermore, we are exploring spintronic devices in 3-dimensional platforms where new physics and unveiled domain wall dynamics arise [8]. To achieve the 3-dimensional structure, we use the multi-photon lithography technique where nanoscopic 3D structures are possible. Shifting from 2D to 3D will also allow us to create devices with richer functionalities and a higher data storage capacity in a given device area. Integrating high-dimensional geometry, racetrack memory will have a significant impact on the future of the memory industry [6]. For spintronics research, we are also actively collaborating with Samsung electronics, South Korea, for the development of domain wall based memories.

For the success of the research, one requires comprehensive and deep understanding of relevant instruments. Our Multi-source, atomically engineered, next-generation, alloys and compounds deposition system (MANGO) will be available for highly complex material science. Cutting-edge electron beam lithography and ion beam etching tools will be accessible for the design of novel nanoscopic spintronic devices. Furthermore, high-quality electronics (high-speed RF source, DC measurement, network analyzer, lock-in technique) are available for electrical transport and magneto-optical microscopy measurements. We seek highly creative, self-motivated, and self-organized candidates with team spirit. Experiences in spintronics, material deposition, and device fabrication are a plus (but not mandatory). It is expected that the doctoral candidate works with a wide variety of instruments. The candiate will have the opportunity to work with team members with diverse expertise.

Literature:

[1] P. Wang et al., Adv. Mat. 34 (2022)

[2] B. Hazra et al., Nat. Commun. 14 (2023)

[3] B. Pal et al., Sci. Adv. 8 (2022)

[4] Y. Guan et al., Adv. Mater. 33 (2021)

[5] S. S. P. Parkin and S.-H. Yang, Nat. Nanotechnol. 10 (2015)

[6] S. S. P. Parkin et al., Science 320, (2008)

[7] J. Yoon et al., Nat. Nanotechnol. 17 (2022)

[8] K. Gu et al., Nat. Nanotechnol. 17 (2022)

Contact:

For scientific questions about the possible PhD topic, please contact Dr. Jae-Chun Jeon. For formal question regarding the application, please contact Michael Strauch.