Room-temperature magnetoresistance in an all-antiferromagnetic tunnel junction

Antiferromagnetic spintronics(1-16) is a rapidly growing field in condensed-matter physics and information technology with potential applications for high-density and ultrafast information devices. However, the practical application of these devices has been largely limited by small electrical outputs at room temperature. Here we describe a room-temperature exchange-bias effect between a collinear antiferromagnet, MnPt, and a non-collinear antiferromagnet, Mn3Pt, which together are similar to a ferromagnet-antiferromagnet exchange-bias system. We use this exotic effect to build all-antiferromagnetic tunnel junctions with large nonvolatile room-temperature magnetoresistance values that reach a maximum of about 100%. Atomistic spin dynamics simulations reveal that uncompensated localized spins at the interface of MnPt produce the exchange bias. First-principles calculations indicate that the remarkable tunnelling magnetoresistance originates from the spin polarization of Mn3Pt in the momentum space. All-antiferromagnetic tunnel junction devices, with nearly vanishing stray fields and strongly enhanced spin dynamics up to the terahertz level, could be important for next-generation highly integrated and ultrafast memory devices(7,9,16).

Automated summary

Antiferromagnetic spintronics is a growing field with potential applications in high-density and ultrafast information devices. We describe an exchange-bias effect between collinear antiferromagnet MnPt and non-collinear antiferromagnet Mn3Pt at room temperature, which enables the construction of all-antiferromagnetic tunnel junctions with large nonvolatile magnetoresistance. Atomistic spin dynamics simulations reveal the origin of this effect at the interface of MnPt, while first-principles calculations explain the high magnetoresistance from the spin polarization of Mn3Pt in momentum space. These all-antiferromagnetic tunnel junction devices with minimal stray fields and enhanced spin dynamics could be important for future memory devices.