Measurement of the spin-transfer-torque vector in magnetic tunnel junctions

By J. Sankey, Yongwei Cui, Jonathan Z. Sun, J. Slonczewski, Robert A. Buhrman, D. Ralph. 2007

563 citations recorded by the source corpus.

The transfer of spin angular momentum from a spin-polarized current to a ferromagnet can generate sufficient torque to reorient the magnet’s moment. This torque could enable the development of efficient electrically actuated magnetic memories and nanoscale microwave oscillators. Yet difficulties in making quantitative measurements of the spin-torque vector have hampered understanding. Here we present direct measurements of both the magnitude and direction of the spin torque in magnetic tunnel junctions, the type of device of primary interest for applications. At low bias V, the differential torque dτ/dV lies in the plane defined by the electrode magnetizations, and its magnitude is in excellent agreement with recent predictions for near-perfect spin-polarized tunnelling. We find that the strength of the in-plane differential torque remains almost constant with increasing bias, despite a substantial decrease in the device magnetoresistance, and that with bias the torque vector also rotates out of the plane.

Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics

View Paper: https://www.semanticscholar.org/paper/34a3e6ab24c321b9d1bc74cc5310fcce63f400c7

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In Atomic and Molecular Physics, and Optics

In Condensed Matter Physics

Citations in the corpus

Basic principles of STT-MRAM cell operation in memory arrays (2013, background): “Interestingly, this bias dependence of the STT efficiency is still significantly less strong than the bias dependence of the TMR [41, 52].”
Electrical Detection of Magnetization Dynamics via Spin Rectification Effects (2016, methodology): “[28] Use of SR to measure bias and angular dependence of STT vector in CoFeB/MgO/CoFeB MTJ”
Vertical-current-induced domain-wall motion in MgO-based magnetic tunnel junctions with low current densities (2011, methodology): “On the contrary, the inplane torque TIP can only induce a small shift of the DW of a few nm.”
Interface-Induced Phenomena in Magnetism (2016, unknown): “This additional voltage is due to a current-induced shift δδRR of time-average resistance of the magnetic tunnel junction from its equilibrium value [Sankey et al., 2008; Miwa et al., 2014].”
Spin-Torque and Spin-Hall Nano-Oscillators (2015, background): “While the perpendicular contribution is small for all-metallic multilayers [45]–[47], it can be substantial in devices with tunneling barriers [46], [48]–[50].”