Bias-driven high-power microwave emission from MgO-based tunnel magnetoresistance devices

Abstract

Spin-momentum transfer between a spin-polarized current and a ferromagnetic layer can induce steady-state magnetization precession, and has recently beenproposed as a working principle for ubiquitous radio-frequency devices for radar and telecommunication applications. However, to-date, the development of industrially attractive prototypes has been hampered by the inability to identify systems which can provide enough power. Here, we demonstrate that microwave signals with device-compatible output power levels can be generated from a single magnetic tunnel junction with a lateral size of 100 nm, seven orders of magnitude smaller than conventional radio-frequency oscillators. We find that in MgO magnetic tunnel junctions the perpendicular torque induced by the spin-polarized current on the local magnetization can reach 25% of the in-plane spin-torque term, while exhibiting a different bias-dependence. Both findings contrast with the results obtained on all-metallic structures -previously investigated -, reflecting the fundamentally different transport mechanisms in the two types of structures.Mizuguchi for discussions.

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

“…2,3 Moreover, STT is utilized in MTJ nano-oscillators that generate signals in the GHz frequency range. [4][5][6] In order to optimize MTJ parameters, so that they can compete with existing memory and microwave technologies, it is necessary to fully understand STT. The spin-torque diode effect enables quantitative measurements of STT parameters.…”

Micromagnetic simulations of magnetization dynamics in a nanowire induced by a spin-polarized current injected via a point contact

“…Practical applications of spin torque nano-oscillators (STNOs) require high output power levels and low phase noise 8,9,10 . Several approaches pursuing these goals, such as phase locking of arrays of STNOs 11,12,13,14 and development of STNOs based on magnetic tunnel junctions 15,16,17,18 are active areas of research.…”

Thermal electric effects in Fe|GaAs|Fe tunnel junctions

“…[16][17][18][19] Spin-dependent Seebeck effects in MTJs have been computed 20 and measured. [21][22][23] A spin accumulations has been injected thermally into silicon by permalloy contacts through MgO tunnel junctions.…”