Tunneling magnetoresistance in magnetic tunnel junctions with a single ferromagnetic electrode

Abstract

Magnetic tunnel junctions (MTJs) are key components of spintronic devices, such as magnetic random-access memories. Normally, MTJs consist of two ferromagnetic (FM) electrodes separated by an insulating barrier layer. Their key functional property is tunneling magnetoresistance (TMR) that is a change in MTJ's resistance when magnetization of the two electrodes alters from parallel to antiparallel. Here, we demonstrate that TMR can occur in MTJs with a single FM electrode, provided that the counter electrode is an antiferromagnetic (AFM) metal that supports a spin-split band structure and/or a Néel spin current. Using RuO${}_2$ as a representative example of such antiferromagnet and CrO${}_2$ as a FM metal, we design all-rutile RuO${}_2$/TiO${}_2$/CrO${}_2$ MTJs to reveal a non-vanishing TMR. Our first-principles calculations predict that magnetization reversal in CrO${}_2$ significantly changes conductance of the MTJs stacked in the (110) or (001) planes. The predicted giant TMR effect of about 1000% in the (110) oriented MTJs stems from spin-dependent conduction channels in CrO${}_2$ (110) and RuO${}_2$ (110), whose matching alters with CrO${}_2$ magnetization orientation, while TMR in the (001) oriented MTJs originates from the Néel spin currents and different effective TiO${}_2$ barrier thickness for the two magnetic sublattices that can be engineered by the alternating deposition of TiO${}_2$ and CrO${}_2$ monolayers. Our results demonstrate a possibility of a sizable TMR in MTJs with a single FM electrode and offer a practical test for using the altermagnet RuO${}_2$ in functional spintronic devices.

7 pages, 5 Figures

References in corpus (7)

• Sequential Edge-Epitaxy in 2D Lateral Heterostructures
• Antiferromagnetism in RuO${}_2$ as $d$-wave Pomeranchuk instability
• Itinerant Antiferromagnetism in RuO${}_2$
• Tunneling Magnetoresistance in Noncollinear Antiferromagnetic Tunnel Junctions
• Néel Spin Currents in Antiferromagnets
• Crystal facet orientated Altermagnets for detecting ferromagnetic and antiferromagnetic states by giant tunneling magnetoresistance effect
• Detection of current-induced spins by ferromagnetic contacts

Cited by in corpus (15)

• Antiferroelectric Altermagnets: Antiferroelectricity Alters Magnets
• Spin-Polarized Antiferromagnetic Spintronics
• Impurity-induced Friedel oscillations in altermagnets and $p$-wave magnets
• Anisotropic spin filtering by an altermagnetic barrier in magnetic tunnel junctions
• First-principles study on tunnel magnetoresistance effect with Cr-doped RuO${}_2$ electrode
• Altermagnetic Flatband-Driven Fermi Surface Geometry for Giant Tunneling Magnetoresistance
• Exploration of Altermagnetism in $\mathrm{Ru}{\mathrm{O}}_2$
• Symmetry-controlled SrRuO3/SrTiO3/SrRuO3 magnetic tunnel junctions:Spin polarization and its relevance to tunneling magnetoresistance
• Viscoelastic tensor and hydrodynamics of altermagnets
• Spin Hall magnetoresistance at the altermagnetic insulator/Pt interface
• Approaches to tunnel magnetoresistance effect with antiferromagnets
• Tailoring Corner States and Exceptional Points in Altermagnets
• Néel vector controlled charge and spin transport in altermagnetic junctions
• Altermagnetism from the viewpoint of chemistry
• 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