Spin-orbit torque phenomena in complex oxide heterostructures
ABSTRACT
Energy-efficient magnetic spin orbit torque nano-oscillators and coupled oscillator arrays are being explored for low-power neuromorphic computing systems [1, 2]. Commonly studied oscillator systems are mostly based on metallic bilayers of ferromagnet (FM)/ heavy metals (HM) (FM=CoFeB, Py and NM=Pt, Ta, W). I will discuss recent efforts to replace the metallic layers with complex oxides with coupled spin, electron and lattice degrees of freedom [2]. Large spin-charge conversion, low damping, and small resonance linewidth are essential constituents for the development of energy efficient oscillators. In this regard half-metallic perovskite ferromagnet, La0.67Sr0.33MnO3 (LSMO) films are studied as the magnetic free layers [3] combined with transition metal oxides such as iridates (e.g. IrO2, SrIrO3, etc.) and NdNiO3(NNO) as the spin-orbit torque layer providing potentially new functionality. For example, IrO2 has a unique electronic structure, where the density of states near the Fermi level is dominated by only 5d electrons with strong spin-orbit coupling and large charge to spin conversion [4]. NNO exhibits a first-order metal-insulator transition near 200K in bulk. The onset of the metal-insulator phase transition is also accompanied by a complex E’ type anti-ferromagnetic ordering in this material. We observe thickness and temperature dependent modulation of spin-charge conversion through the phase transition of NNO and harness the disorder in NNO to generate a pronounced enhancement of the inverse spin Hall effect signal at the transition temperature [5]. Finally progress towards an all-oxide nano-oscillator will be discussed. This work is supported by the U.S. Department of Energy under Grant No. DE-SC0019273.
[1] J. Grollier et al., Nature electronics 3, 360 (2020).
[2] A. Hoffmann et al., APL Materials 10, 070904 (2022).
[3] Sahoo et al., Adv. Mater. Interfaces, 2401038 (2025).
[4] Sahoo, Frano and Fullerton, Appl. Phys. Lett. 123, 032404 (2023).
[5] Sahoo, et al. submitted for publication (2025).
Date and Time
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- Date: 13 Jun 2025
- Time: 12:00 PM UTC to 01:00 PM UTC
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- Campus Artem,
- 2 allée André Guinier,
- Nancy , Lorraine
- France 54011
- Building: Institut Jean Lamour
- Room Number: Alnot 4-A014,
- Starts 01 June 2025 10:00 PM UTC
- Ends 12 June 2025 10:00 PM UTC
- No Admission Charge
Speakers
Eric Fullerton
Biography:
Bio: Eric Fullerton is a Distinguished Professor at the University of
California, San Diego in the Departments of Electrical and Computer
Engineering and Chemical and Nano Engineering and is an Endowed Chair
and Director of the Center for Memory and Recording Research. He
received his B.Sc. in Physics from Harvey Mudd College in 1984 and his
Ph.D. in Physics from UC San Diego in 1991. Previously to joining UC San
Diego he held research positions at Argonne National Laboratory, the IBM
Almaden Research Center and Hitachi Global Storage Technologies. His
current research focuses on the synthesis and characterization of magnetic
nanostructures, both as a probe of materials in reduced dimensions and for
the development of novel information technologies. He has co- authored >420 journal articles, been
issued 51 US patents, is a Fellow of the American Physical Society and the IEEE and is a member of
the National Academy of Engineering.
Mohammed Balli
Biography:
Mohamed Balli is Full Professor at International University of Rabat (Morocco), Associate Professor at Sherbrooke University (Canada) & Adjunct Full professor at Mississippi State University (USA). He aims to understand how to particularly make functional materials useful in our daily life such as in clean and efficient refrigeration/heating, hydrogen storage, solar cells, batteries and much more. M. Balli received his master’s degree in Mechanics of Materials from Montpellier II University (2003, France), a second master’s degree in Magnetism from Joseph Fourier University, Grenoble 1 (2004, France) and, a PhD degree (2007) in physics of materials, from Joseph Fourier University, prepared at Néel Institute (CNRS). M. Balli has occupied several academic and research positions in France, Switzerland and Canada. His research work has received numerous awards including, "Rising star researcher award" given by the Research Fund: Nature and Technology, Canada (2014) and the “Research and Innovation Prize 2015” from Sherbrooke University. He is classified at the top 2% scientists in the world by Stanford University (2024).
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