Crystal facet orientated Altermagnets for detecting ferromagnetic and antiferromagnetic states by giant tunneling magnetoresistance effect

Abstract

Emerging altermagnetic materials with vanishing net magnetizations and unique band structures have been envisioned as an ideal electrode to design antiferromagnetic tunnel junctions. Their momentum-resolved spin splitting in band structures defines a spin-polarized Fermi surface, which allows altermagnetic materials to polarize current as a ferromagnet, when the current flows along specific directions relevant to their altermagnetism. Here, we design an Altermagnet/Insulator barrier/Ferromagnet junction, renamed as altermagnetic tunnel junction (ATMTJ), using RuO${}_2$/TiO${}_2$/CrO${}_2$ as a prototype. Through first-principles calculations, we investigate the tunneling properties of the ATMTJ along the [001] and [110] directions, which shows that the tunneling magnetoresistance (TMR) is almost zero when the current flows along the [001] direction, while it can reach as high as 6100\% with current flows along the [110] direction. The spin-resolved conduction channels of the altermagnetic RuO${}_2$ electrode are found responsible for this momentum-dependent (or transport-direction-dependent) TMR effect. Furthermore, this ATMTJ can also be used to readout the Néel vector of the altermagnetic electrode RuO${}_2$. Our work promotes the understanding toward the altermagnetic materials and provides an alternative way to design magnetic tunnel junctions with ultrahigh TMR ratios and robustness of the altermagnetic electrode against external disturbance, which broadens the application avenue for antiferromagnetic spintronic devices.

References in corpus (5)

• Altermagnetism: spin-momentum locked phase protected by non-relativistic symmetries
• Giant and tunneling magnetoresistance effects from anisotropic and valley-dependent spin-momentum interactions in antiferromagnets
• Itinerant Antiferromagnetism in RuO${}_2$
• Prediction of low-Z collinear and noncollinear antiferromagnetic compounds having momentum-dependent spin splitting even without spin-orbit coupling
• Tunneling Magnetoresistance in Noncollinear Antiferromagnetic Tunnel Junctions

Cited by in corpus (26)

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• Altermagnetic variants in thin films of Mn5Si3
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• Evidence for single variant in altermagnetic RuO2(101) thin films
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• Lithium and Vanadium Intercalation into Bilayer V2Se2O: Ferrimagnetic-Ferroelastic Multiferroics and Anomalous and Spin Transport
• First-principles study on tunnel magnetoresistance effect with Cr-doped RuO${}_2$ electrode
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• Tunneling magnetoresistance in a junction made of $X$-wave magnets with $X=p,d,f,g,i$
• Approaches to tunnel magnetoresistance effect with antiferromagnets
• Tailoring Corner States and Exceptional Points in Altermagnets
• Spin-Polarized Magnetic Metal Electrodes for Magnetic Tunnel Junctions
• Ab initio study of magnetoresistance effect in $\mathrm{M}{\mathrm{n}}_3\mathrm{Sn}/\mathrm{MgO}/\mathrm{M}{\mathrm{n}}_3\mathrm{Sn}$ antiferromagnetic tunnel junction
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