December 1 - 6, 2024
Boston, Massachusetts
Symposium Supporters
2024 MRS Fall Meeting & Exhibit
QT02.07.01

Spin-Orbit Torque Phenomena in Complex Oxide Heterostructures

When and Where

Dec 4, 2024
8:30am - 9:00am
Sheraton, Fifth Floor, Public Garden

Presenter(s)

Co-Author(s)

Eric Fullerton1

University of California, San Diego1

Abstract

Eric Fullerton1

University of California, San Diego1
Energy-efficient magnetic spin orbit torque nano-oscillators and coupled oscillator arrays are being explored for low-power neuromorphic computing systems [1]. Commonly studied oscillator material systems are mostly based on metallic ferromagnet(FM)/ heavy metal(HM) (FM=CoFeB, Py, NM=Pt, Ta, W) bilayers with a relatively high intrinsic Gilbert damping of the order of 10-2. 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 development of energy efficient oscillators. In this regard half-metallic perovskite ferromagnet, La0.67Sr0.33MnO3 (LSMO) is studied as the magnetic free layer combined with transition metal oxides such IrO2, CaIrO3.and NdNiO3 as the spin-orbit torque layer provide potentially new functionality. LSMO has a very low damping that is anisotropic in the plane and nearly 100% spin polarization giving large spin torque signals. IrO2 and CaIrO3 have unique electronic structures, 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 [3]. NdNiO3 (NNO) exhibits a first-order metal-insulator transition centered at 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. Spin-orbit torque measurement of the constituent materials and progress towards an all oxide nano-oscillator will be discussed. The work is done in collaboration with Biswajit Sahoo, K. Akilan, Sarmistha Das, Sébastien Petit-Watelot, Carlos Rojas, and Alex Frano and supported by US Department of Energy under Grant No. DE-SC0019273.

[1] J. Grollier et al., Nature electronics 3 (7), 360 (2020).
[2] Imada, Fujimori and Tokura, Rev. Mod. Phys. 70, 1039 (1998)
[3] Sahoo, Frano and Fullerton, Appl. Phys. Lett. 123, 032404 (2023).

Symposium Organizers

Chiara Ciccarelli, University of Cambridge
Tobias Kampfrath, Freie Universität Berlin
Roberto Mantovan, CNR-IMM, Univ of Agrate Brianza
Jianhua Zhao, Chinese Academy of Sciences

Session Chairs

Saroj Dash
Andrew Kent

In this Session