Interfacial Origin of Unconventional Spin-Orbit Torque in Py/r-IrMn3

• Angle-resolved spin-torque ferromagnetic resonance measurements are carried out in heterostructures consisting of Py (Ni81Fe19) and a noncollinear antiferromagnetic quantum material r-IrMn3. The structural characterization reveals that r-IrMn3 is polycrystalline in nature. A large exchange bias of 158 Oe is found in Py/r-IrMn3 at room temperature, while r-IrMn3/Py and Py/Cu/r-IrMn3 exhibit no exchange bias. Regardless of the exchange bias and stacking sequence, a substantial unconventional out-of-plane anti-damping torque is observed when r-IrMn3 is in direct contact with Py. The magnitude of the out-of-plane spin-orbit torque efficiency is found to be twice as large as the in-plane spin-orbit torque efficiency. The unconventional spin-orbit torque vanishes when a Cu spacer is introduced between Py and r-IrMn3, indicating that the unconventional spin-orbit torque in this system originates at the interface. These findings are important for realizing efficient antiferromagnet-based spintronic devices via interfacial engineering.

Ämnesord

NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

Nyckelord

?-IrMn3

non-collinear antiferromagnet

spin-torque ferromagnetic

reso-nance

unconventional torque

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