Evidence for single variant in altermagnetic RuO2(101) thin films

Abstract

Altermagnetism presents intriguing possibilities for spintronic devices due to its unique combination of strong spin-splitting and zero net magnetization. However, realizing its full potential hinges on fabricating single-variant altermagnetic thin films. In this work, we present definitive evidence for the formation of single-variant altermagnetic RuO2(101) thin films with fully epitaxial growth on Al2O3(1-102) r-plane substrates, confirmed through rigorous structural analyses using X-ray diffraction, atomic-resolution transmission electron microscopy and X-ray magnetic linear dichroism. The mutual correspondence of the occupancy of oxygen atoms on the surfaces of RuO2(101)[010] and Al2O3(1-102)[11-20] plays a decisive role in the formation of the single-variant RuO2, which is also supported by our first-principles density functional theory calculations. We further observed spin-splitting magnetoresistance in the single-variant RuO2(101)/CoFeB bilayers, highlighting the characteristic effect of single variant on spin transport. The demonstration of single-variant RuO2(101) films marks a significant advancement in the field of altermagnetism and paves the way for exploring their potential applications.

38 pages, 13 figures

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Cited by in corpus (6)

• All-electrically controlled spintronics in altermagnetic heterostructures
• Absence of transport altermagnetic spin-splitting effect in RuO2
• Exploration of Altermagnetism in $\mathrm{Ru}{\mathrm{O}}_2$
• Surface-Localized Magnetic Order in RuO2 Thin Films Revealed by Low-Energy Muon Probes
• Giant Room-Temperature Third-Order Electrical Transport in a Thin-Film Altermagnet Candidate
• Absence of magnetic order in epitaxial RuO2 revealed by X-ray linear dichroism