Title
Spin Torque Efficiency and Analytic Error Rate Estimates of Skyrmion Racetrack Memory
Author
Dieter Suess
Author
Florian Bruckner
... show all
Abstract
In this paper, the thermal stability of skyrmion bubbles and the critical currents to move them over pinning sites were investigated. For the used pinning geometries and the used parameters, the unexpected behavior is reported that the energy barrier to overcome the pinning site is larger than the energy barrier of the annihilation of a skyrmion. The annihilation takes place at boundaries by current driven motion, as well as due to the excitation over energy barriers, in the absence of currents, without forming Bloch points. It is reported that the pinning sites, which are required to allow thermally stable bits, significantly increase the critical current densities to move the bits in skyrmion-like structures to about jcrit = 0.62 TA/m². The simulation shows that the applied spin transfer model predicts experimentally obtained critical currents to move stable skyrmions at room temperature well, which is in contrast to simulations based on spin orbit torque that predict significantly too low critical currents. By calculating the thermal stability, as well as the critical current, we can derive the spin torque efficiency η = ΔE/Ic = 0.19 kBT300/μA, which is in a similar range to the simulated spin torque efficiency of MRAM structures. Finally, it is shown that the stochastic depinning process of any racetrack-like device requires an extremely narrow depinning time distribution smaller than ~6% of the current pulse length to reach bit error rates smaller than 10−9.
Keywords
Magnetic properties and materialsSpintronics
Object type
Language
English [eng]
Persistent identifier
https://phaidra.univie.ac.at/o:1177534
Appeared in
Title
Scientific Reports
Volume
9
ISSN
2045-2322
Issued
2019
Publisher
Springer Science and Business Media LLC
Date issued
2019
Access rights
Rights statement
© The Author(s) 2019

Download

University of Vienna | Universitätsring 1 | 1010 Vienna | T +43-1-4277-0