The giant and tunneling magnetoresistance effects are widely use in commercial spintronics devices as platform technologies for magnetic-field sensors in magnetic recording. These rely on ferromagnets to spin-polarize and detect an electronic current. The recent discovery of altermagnetism has disrupted this paradigm, demonstrating that even spin-neutral currents can yield significant magnetoresistance. Using first-principles calculations, we confirm the momentum-dependent spin-splitting band structure of the altermagnet ${\mathrm{KV}}_2{\mathrm{Se}}_2\mathrm{O}$ and design an all-metal device, ${\mathrm{KV}}_2{\mathrm{Se}}_2\mathrm{O}/{\mathrm{BaTi}}_2{\mathrm{Bi}}_2\mathrm{O}/{\mathrm{KV}}_2{\mathrm{Se}}_2\mathrm{O}$, displaying tunnel-like transport and the enormous magnetoresistance ratio of $1.5\times {10}^{12}\%$. This is orders of magnitude larger than what was previously reported for altermagnetic tunnel junctions. The underpinning mechanism of this remarkable magnetoresistance is symmetry-driven spin selectivity, which here is explained by computing spin transport across ${\mathrm{KV}}_2{\mathrm{Se}}_2\mathrm{O}$ in different magnetic configurations. Our study expands the possible use of altermagnets in spintronics and suggests a new avenue for high-performing antiferromagnetic devices.

Close

PrevNext

View figure in article

• Altermagnetism
• Spintronics
• Tunneling magnetoresistance
• Altermagnets
• Magnetic tunnel junctions
• Metals
• Oxides
• Density functional calculations