Influence of MgO tunnel barrier thickness on spin-transfer ferromagnetic resonance and torque in magnetic tunnel junctions

Abstract

Spin-transfer ferromagnetic resonance (ST-FMR) in symmetric magnetic tunnel junctions (MTJs) with a varied thickness of the MgO tunnel barrier (0.75 nm < $t_{MgO}$ < 1.05 nm) is studied using the spin-torque diode effect. The application of an RF current into nanosized MTJs generates a DC mixing voltage across the device when the frequency is in resonance with the resistance oscillations arising from the spin transfer torque. Magnetization precession in the free and reference layers of the MTJs is analyzed by comparing ST-FMR signals with macrospin and micromagnetic simulations. From ST-FMR spectra at different DC bias voltage, the in-plane and perpendicular torkances are derived. The experiments and free-electron model calculations show that the absolute torque values are independent of tunnel barrier thickness. The influence of coupling between the free and reference layer of the MTJs on the ST-FMR signals and the derived torkances are discussed.

arXiv comment6 pages, 5 figures

References in corpus (14)

• Measurement of the Spin-Transfer-Torque Vector in Magnetic Tunnel Junctions
• Observation of spin-transfer switching in deep submicron-sized and low-resistance magnetic tunnel junctions
• Bias-driven large power microwave emission from MgO-based tunnel magnetoresistance devices
• Spin-transfer-driven ferromagnetic resonance of individual nanomagnets
• Excitations of incoherent spin-waves due to spin-transfer torque
• Vertical current induced domain wall motion in MgO-based magnetic tunnel junction with low current densities
• Ab initio studies of the spin-transfer torque in tunnel junctions
• Time-resolved detection of spin-transfer-driven ferromagnetic resonance and spin torque measurement in magnetic tunnel junctions
• Bias and angular dependence of spin-transfer torque in magnetic tunnel junctions
• Quantized spin wave modes in magnetic tunnel junction nanopillars
• Nonlinear bias dependence of spin-transfer torque from atomic first principles
• Spin transfer torque oscillator based on asymmetric magnetic tunnel junctions
• Spin-Torque Diode Measurements of MgO-Based Magnetic Tunnel Junctions with Asymmetric Electrodes
• Inductive determination of the optimum tunnel barrier thickness in magnetic tunnelling junction stacks for spin torque memory applications

Cited by in corpus (4)

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