Low operational current spin Hall nano-oscillators based on NiFe/W bilayers

Mazraati, Hamid; Chung, Sunjae; Houshang, Afshin; Dvornik, Mykola; Piazza, Luca; Qejvanaj, Fatjon; Jiang, Sheng; Le, Tuan Quang; Weissenrieder, Jonas; Åkerman, Johan

doi:10.1063/1.4971828

Cited by 66 publications

(50 citation statements)

References 38 publications

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“…Prominent examples of such systems are the so-called nano-constriction 25,26 and nanowire 27,28 based spin Hall nano-oscillators [29][30][31] (SHNOs), where pure spin currents are injected from the heavy metal (such as Pt or W) to the adjoint ferromagnetic layer (e.g. NiFe or CoFeB).…”

Section: Introductionmentioning

confidence: 99%

Origin of Magnetization Auto-Oscillations in Constriction-Based Spin Hall Nano-Oscillators

2018

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We use micromagnetic simulations to map out and compare, the linear and auto-oscillating modes in constriction-based spin Hall nano-oscillators as a function of applied magnetic field with varying magnitude and out-of-plane angle. We demonstrate that for all possible applied field configurations the auto-oscillations emerge from the localized linear modes of the constriction. For field directions tending towards the plane, these modes are of the so-called "edge" type, i.e. localized at the opposite sides of the constriction. When the magnetization direction instead approaches the film normal, the modes transform to the so-called "bulk" type, i.e. localized inside the constriction with substantially increased precession volume, consistent with the re-distribution of the magnetic charges from the sides to the top and bottom surfaces of the constriction. In general, the threshold current of the corresponding auto-oscillations increases with the applied field strength and decreases with its outof-plane angle, consistent with the behavior of the internal field and in good agreement with a macrospin model. A quantitative agreement is then achieved by taking into account the strongly non-uniform character of the system via a mean-field approximation. Both the Oe field and the spin transfer torque from the drive current increase the localization and decrease the frequency of the observed mode. Furthermore, the anti-symmetric Oe field breaks the lateral symmetry, favoring the localized mode at one of the two constriction edges, in particular for large out-of-plane field angles where the threshold current is significantly increased and the edge demagnetization is suppressed.

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Section: Introductionmentioning

confidence: 99%

Origin of Magnetization Auto-Oscillations in Constriction-Based Spin Hall Nano-Oscillators

2018

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“…In certain materials (e.g. Pt [13], Ta [27] and W [28], [29]), the conversion ratio from charge to spin current, called spin-Hall angle (SHA) is large enough to exert a sufficient torque on an adjacent FL to excite magnetization precession. The three-terminal MTJ-SHNO architecture proposed in [16] is based on these principles where a Ta strip is providing spin injection into the FL.…”

Section: A Basic Operation Of Three-terminal Mtj-shnos With Vcmamentioning

confidence: 99%

Compact Macrospin-Based Model of Three-Terminal Spin-Hall Nano Oscillators

et al. 2019

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“…As a flow of angular momentum that does not accompany a charge flow, pure spin currents carry information with minimum power dissipation [14]. More importantly, similar to spin-polarized current, pure spin currents are capable of manipulating the magnetization of ferromagnetic elements, showing promising application perspectives in alternative information recording and data processing devices such as spin orbital torque magnetic random access memory (SOT MRAM) [15] and spin Hall nano-oscillators [16]. In a ferromagneticnonmagnetic (FM NM) bilayer system, pure spin currents can be converted by charge current flowing through NM with strong spin orbit coupling (spin Hall effect), then propagate into the adjacent FM, thereby affecting the magnetic fluctuation, magnetization dynamics, and even magnetization switching [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Strain-Enhanced Charge-to-Spin Conversion in Ta/Fe/Pt Multilayers Grown on Flexible Mica Substrate

et al. 2019

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Recent demonstration of magnetization manipulation has been focused on the utilization of pure spin current converted by charge current in nonmagnetic materials with strong spin-orbit coupling (SOC), which stimulates intensive studies on the exploration of materials with larger SOC, such as heavy metals and topological insulators. We suggest an alternative approach for enhancing the effective charge-tospin conversion efficiency by applying strain in Ta/Fe/Pt films grown on flexible mica substrates. We experimentally demonstrate a large and tunable charge-to-spin conversion efficiency in Ta/Fe/Pt films by applying compressive strain within a flexible substrate, and over 50% enhancement of effective spin Hall angle eff SHE of up to approximately 0.2 is achieved in a 6.26‰ strained film. Our findings may spur further work on the integration of flexible electronics and SOC and may potentially lead to the innovation of alternative flexible spintronics devices.

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Low operational current spin Hall nano-oscillators based on NiFe/W bilayers

Cited by 66 publications

References 38 publications

Origin of Magnetization Auto-Oscillations in Constriction-Based Spin Hall Nano-Oscillators

Origin of Magnetization Auto-Oscillations in Constriction-Based Spin Hall Nano-Oscillators

Compact Macrospin-Based Model of Three-Terminal Spin-Hall Nano Oscillators

Strain-Enhanced Charge-to-Spin Conversion in Ta/Fe/Pt Multilayers Grown on Flexible Mica Substrate

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