Spin-torque switching efficiency in CoFeB-MgO based tunnel junctions

Sun, J. Z.; Brown, S. L.; Chen, W.; Delenia, E.; Gaidis, M. C.; Harms, J.; Hu, G.; Jiang, Xin; Kilaru, Rohit; Kula, Witold; Lauer, G.; Liu, L. Q.; Murthy, S.; Nowak, Janusz; O’Sullivan, E. J.; Parkin, Stuart S. P.; Robertazzi, R. P.; Rice, Philip M.; Sandhu, Gurtej; Topuria, Teya; Worledge, D. C.

doi:10.1103/physrevb.88.104426

Cited by 110 publications

(53 citation statements)

References 18 publications

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“…It is one of fundamental physical quantities in ferromagnetic materials and affects the switching characteristics of STT-MRAM as well as the DW depinning mechanism because of the domain wall energy. [27][28][29][30] By comparison with the Damon-Eshbach and 1st order bulk modes, as shown in Fig. 6, A ex is determined to be 0.48 Â 10 À6 erg/cm, which is much smaller than other magnetic materials, such as CoFeB (1.0 $ 2.8 Â 10 À6 erg/cm), Co (3.0 Â 10 À6 erg/cm), and Co/Pt (1.4 $ 2.2 Â 10 À6 erg/cm).…”

Section: Resultsmentioning

confidence: 99%

Field-induced domain wall motion of amorphous [CoSiB/Pt]N multilayers with perpendicular anisotropy

Choi¹,

Lee²,

Yoon³

et al. 2014

Journal of Applied Physics

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Articles you may be interested inAmorphous FeCoSiB for exchange bias coupled and decoupled magnetoelectric multilayer systems: Realstructure and magnetic properties J. Appl. Phys. 116, 134302 (2014); 10.1063/1.4896662 Time-dependent magnetization reversal in amorphous CoSiB/Pd multilayers with perpendicular magnetic anisotropy Valve behavior of giant magnetoimpedance in field-annealed Co 70 Fe 5 Si 15 Nb 2.2 Cu 0.8 B 7 amorphous ribbonAmorphous CoSiB/Pt multilayer is a perpendicular magnetic anisotropy material to achieve high squareness, low coercivity, strong anisotropy, and smooth domain wall (DW) motion, because of the smoother interface compared with crystalline multilayers. For [CoSiB(6 Å )/Pt (14 Å )] N multilayers with N ¼ 3, 6, and 9, we studied the field-induced DW dynamics. The effective anisotropy constant K 1 eff is 1.5 Â 10 6 erg/cm 3 for all the N values, and the linear increment of coercive field H c with N gives constant exchange coupling J. By analyzing the field dependence of DW images at room temperature, a clear creep motion with the exponent l ¼ 1/4 could be observed. Even though the pinning field H dep slightly increases with N, the pinning potential energy U c is constant (¼35 k B T) for all the N values. These results imply that the amorphous [CoSiB/Pt] N multilayers are inherently homogeneous compared to crystalline multilayers. For N 6, the pinning site density q pin is less than 1000/lm 2 , which is about 1 pinning site per the typical device junction size of 30 Â 30 nm 2 . Also, the exchange stiffness constant A ex is obtained to be 0.48 Â 10 À6 erg/cm, and the domain wall width is expected to be smaller than 5.5 nm. These results may be applicable for spin-transfer-torque magnetic random access memory and DW logic device applications. V C 2014 AIP Publishing LLC. [http://dx.

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Section: Resultsmentioning

confidence: 99%

Field-induced domain wall motion of amorphous [CoSiB/Pt]N multilayers with perpendicular anisotropy

Choi¹,

Lee²,

Yoon³

et al. 2014

Journal of Applied Physics

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“…This so-called "high spin torque efficiency" is a strong stimulus for high density MTJ application. Spin torque efficiency is defined here as [85]:…”

Section: Discussionmentioning

confidence: 99%

Current-Induced Magnetic Switching for High-Performance Computing

Zhang

Zhao

Wang

et al. 2015

Spintronics-Based Computing

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“…For macrospin, typical materials parameters would indicate an I c of the order of 30-50 mA if E b % 60k B T where T = 300 K. Of experimentally verified devices with sizes larger than 30 nm or so, the I c tend to be significantly larger than such macrospin-derived values. This is believed to be related to non-macrospin behavior of finite-size devices and in particular a form of thermal and spintorque excitation that is sub-volumes [78,102,103]. Equation 60 indicates a minimum write current independent of junction size if one is to maintain the same data retention lifetime or E b .…”

Section: Spin-torque Switchable Magnetic Tunnel Junction As Memory Dementioning

confidence: 98%

“…Generally speaking, junctions with smaller lateral size in comparison with the magnetic exchange length would have better spin-torque efficiency ratio E b /I c0 . This has recently been experimentally observed in sub-50 nm spin-torque switchable MTJs [78,98,[101][102][103].…”

Section: Spin-torque Switching Efficiency and Control Of Magnetic Animentioning

confidence: 98%

“…Direct comparison with experiment reveals valuable insight into the roles different materials parameters play [76,78,85,100]. Advances of lithography tools and technologies have at the same time enabled fabrication of device structures below 20 nm in size, making it feasible to realize a nearly macrospin-like experimental system, facilitating quantitative comparison with theoretical understanding [78,[101][102][103].…”

Section: Spin-torque-induced Magnetic Excitation and Switchingmentioning

confidence: 99%

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Physical Principles of Spin Torque

Sun

2014

Handbook of Spintronics

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Spin torque refers to the exchange of spin angular momentum between a transport spin current carried by electrons and a ferromagnet. The macroscopic manifestation of this angular momentum exchange is a torque exerted on the ferromagnet by the presence of the spin current. The spin current is often accompanied by a net charge-current transport, although this is not always necessary. There are two types of torque commonly associated with such interactions, one is exchange-like and the other energy nonconserving. These two types of torques have different vectorial relationship with the electron spin polarization and the magnet's moment. The exchange-like torque is in the direction perpendicular to the plane formed by the magnet moment and the spin polarization and is therefore often called the "perpendicular torque." The energy-nonconserving torque lies in the plane, hence the name the "in-plane torque." The perpendicular torque has been known for many decades, as it gives rise to exchange-like coupling between ferromagnetic thin films across a spacer layer of either a nonmagnetic metal or a tunnel barrier. A detailed understanding of the in-plane spin torque has emerged more recently. The in-plane spin torque is associated mainly with nonequilibrium and noncollinear transport of spin current across interfaces between nonmagnetic and ferromagnetic materials. It originates from the dephasing of an electron's spin precession as it enters or leaves a ferromagnet-nonmagnetic interface. The in-plane spin torque gives rise to new dynamic behaviors of the ferromagnet that is the subject of many interesting investigations and with potential for applications. Its physical origin and implications are the main subjects of this review.

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Spin-torque switching efficiency in CoFeB-MgO based tunnel junctions

Cited by 110 publications

References 18 publications

Field-induced domain wall motion of amorphous [CoSiB/Pt]N multilayers with perpendicular anisotropy

Field-induced domain wall motion of amorphous [CoSiB/Pt]N multilayers with perpendicular anisotropy

Current-Induced Magnetic Switching for High-Performance Computing

Physical Principles of Spin Torque

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