Spin-Torque Switching with the Giant Spin Hall Effect of Tantalum

By Luqiao Liu, C. Pai, Yulin Li, H. Tseng, D. Ralph, Robert A. Buhrman. Science, 2012

3,723 citations recorded by the source corpus.

Giant Spin Hall One of the primary challenges in the field of spin-electronics, which exploits the electron's spin rather than its charge, is to create strong currents of electrons with polarized spins. One way to do this is to use a ferromagnet as a polarizer, a principle used in magnetic tunnel junctions; however, these devices suffer from reliability problems. An alternative is the spin Hall effect, where running a charge current through a material generates a spin current in the transverse direction, but the efficiency of this process tends to be small. Liu et al. (p. 555) now show that the spin Hall effect in Tantalum in its high-resistance β phase generates spin currents strong enough to induce switching of the magnetization of an adjacent ferromagnet; at the same time, Ta does not cause energy dissipation in the ferromagnet. These properties allowed efficient and reliable operation of a prototype three-terminal device. Tantalum is found to generate strong spin currents that can induce switching of ferromagnets efficiently and reliably. Spin currents can apply useful torques in spintronic devices. The spin Hall effect has been proposed as a source of spin current, but its modest strength has limited its usefulness. We report a giant spin Hall effect (SHE) in β-tantalum that generates spin currents intense enough to induce efficient spin-torque switching of ferromagnets at room temperature. We quantify this SHE by three independent methods and demonstrate spin-torque switching of both out-of-plane and in-plane magnetized layers. We furthermore implement a three-terminal device that uses current passing through a tantalum-ferromagnet bilayer to switch a nanomagnet, with a magnetic tunnel junction for read-out. This simple, reliable, and efficient design may eliminate the main obstacles to the development of magnetic memory and nonvolatile spin logic technologies.

Subfields: Atomic and Molecular Physics, and Optics, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/9782a75d3377cdcdc7f223bbac8a5be4128bcbe7

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In Atomic and Molecular Physics, and Optics

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Citations in the corpus

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Conduction of spin currents through insulating antiferromagnetic oxides (2013, background): “[18] Liu, L.”
Magnetic texture based magnonics (2020, methodology): “A Pt bar is integrated on top of YIG film a few micrometers away from the gold stripline to vary the magnon chemical potential via the spin Hall effect [290].”
Basic principles of STT-MRAM cell operation in memory arrays (2013, background): “• Family of magnetoelectric effects [95, 96], which can allow magnetization control by electric field without passing electric current through the cell, including recently discovered effect of the voltage-control of anisotropy [97–100]; • Spin-polarized current generation by spin–orbit induced effec”
Spin Hall Effects in Metals (2013, background): “Hall effects in Pt and Ta are large enough for switching via spin transfer torque the magnetization of adjacent ferromagnetic layers [17], [75].”