Ultra-thin lithium aluminate spinel ferrite films with perpendicular magnetic anisotropy and low damping

Xin Yu Zheng; Sanyum Channa; Lauren J Riddiford; Jacob J Wisser; Krishnamurthy Mahalingam; Cynthia T Bowers; Michael E McConney; Alpha T N'Diaye; Arturas Vailionis; Egecan Cogulu; Haowen Ren; Zbigniew Galazka; Andrew D Kent; Yuri Suzuki

doi:10.1038/s41467-023-40733-9

Ultra-thin lithium aluminate spinel ferrite films with perpendicular magnetic anisotropy and low damping

Nat Commun. 2023 Aug 15;14(1):4918. doi: 10.1038/s41467-023-40733-9.

Authors

Xin Yu Zheng^#^{1

2}, Sanyum Channa^#^{3

4}, Lauren J Riddiford^{5

3}, Jacob J Wisser⁶, Krishnamurthy Mahalingam⁷, Cynthia T Bowers⁷, Michael E McConney⁷, Alpha T N'Diaye⁸, Arturas Vailionis^{9

10}, Egecan Cogulu¹¹, Haowen Ren¹¹, Zbigniew Galazka¹², Andrew D Kent¹¹, Yuri Suzuki^{5

3}

Affiliations

¹ Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA. xinzheng@stanford.edu.
² Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA. xinzheng@stanford.edu.
³ Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA, 94305, USA.
⁴ Department of Physics, Stanford University, Stanford, CA, USA.
⁵ Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA.
⁶ National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA.
⁷ Air Force Research Laboratory, Wright Patterson Air Force Base, Dayton, OH, 05433, USA.
⁸ Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
⁹ Stanford Nano Shared Facilities, Stanford University, Stanford, CA, 94305, USA.
¹⁰ Department of Physics, Kaunas University of Technology, Studentu Street 50, LT-51368, Kaunas, Lithuania.
¹¹ Center for Quantum Phenomena, Department of Physics, New York University, New York, NY, 10003, USA.
¹² Leibniz-Institut für Kristallzüchtung, Max-Born-Str. 2, 12489, Berlin, Germany.

^# Contributed equally.

Abstract

Ultra-thin films of low damping ferromagnetic insulators with perpendicular magnetic anisotropy have been identified as critical to advancing spin-based electronics by significantly reducing the threshold for current-induced magnetization switching while enabling new types of hybrid structures or devices. Here, we have developed a new class of ultra-thin spinel structure Li_0.5Al_1.0Fe_1.5O₄ (LAFO) films on MgGa₂O₄ (MGO) substrates with: 1) perpendicular magnetic anisotropy; 2) low magnetic damping and 3) the absence of degraded or magnetic dead layers. These films have been integrated with epitaxial Pt spin source layers to demonstrate record low magnetization switching currents and high spin-orbit torque efficiencies. These LAFO films on MGO thus combine all of the desirable properties of ferromagnetic insulators with perpendicular magnetic anisotropy, opening new possibilities for spin based electronics.