Journal ArticleDOI
Perpendicular-anisotropy CoFeB-MgO magnetic tunnel junctions with a MgO/CoFeB/Ta/CoFeB/MgO recording structure
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TLDR
In this article, the authors investigated a recording structure consisting of two CoFeB-MgO interfaces, MgO/CoFeB (1.6 nm)/Ta (0.4 n) with a recording size of 70 nm.Abstract:
We investigated perpendicular CoFeB-MgO magnetic tunnel junctions (MTJs) with a recording structure consisting of two CoFeB-MgO interfaces, MgO/CoFeB (1.6 nm)/Ta (0.4 nm)/CoFeB (1.0 nm)/MgO. Thermal stability factor of MTJ with the structure having junction size of 70 nmφ was increased by a factor of 1.9 from the highest value of perpendicular MTJs with single CoFeB-MgO interface having the same device structure. On the other hand, intrinsic critical current for spin transfer torque switching of the double- and single-interface MTJs was comparable.read more
Citations
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Journal ArticleDOI
Perpendicular magnetic tunnel junction with enhanced anisotropy obtained by utilizing an Ir/Co interface
TL;DR: In this article, a perpendicularly magnetized storage layer of a spin-torque-switching magnetic random access memory (STT-MRAM) was developed, which attains a perpendicular magnetic anisotropy (PMA) of above 0.9 erg/cm2 at a thickness of 2 nm.
Journal ArticleDOI
Sub-nanosecond spin-torque switching of perpendicular magnetic tunnel junction nanopillars at cryogenic temperatures
TL;DR: In this paper, the authors report the low-temperature nanosecond duration spin-transfer switching characteristics of perpendicular magnetic tunnel junction (pMTJ) nanopillar devices and contrast them to their room temperature properties.
Journal ArticleDOI
Co/Pt multilayer-based magnetic tunnel junctions with a CoFeB/Ta insertion layer
S. Ishikawa,Hiroki Sato,Michihiko Yamanouchi,Shoji Ikeda,Shunsuke Fukami,Fumihiro Matsukura,Hideo Ohno +6 more
Abstract: We investigate properties of magnetic tunnel junctions (MTJs) having a Co/Pt multilayer as a recording layer. A CoFeB layer is inserted between MgO barrier and the recording layer in order to enhance the tunnel magnetoresistance ratio. We show that an additional layer of Ta inserted between CoFeB and Co/Pt multilayer is effective in improving the MTJ properties after annealing. A high effective magnetic anisotropy energy per unit area over 1.2 mJ/m2 is obtained after annealing at 300 °C. Using a 1.6 nm-thick CoFeB insertion layer, both high thermal stability factor of 92 and high tunnel magnetoresistance ratio of 91% are achieved in a MTJ with 17 nm in diameter.
Journal ArticleDOI
CoFeB Thickness Dependence of Damping Constants for Single and Double CoFeB-MgO Interface Structures
TL;DR: In this article, the authors investigated the CoFeB thickness dependence of the damping constant α of single and double coFeB-MgO interface structures by vector-network-analyzer ferromagnetic resonance (VNA-FMR).
Journal ArticleDOI
Magnetization switching diagram of a perpendicular synthetic ferrimagnet CoFeB/Ta/CoFeB bilayer
O. V. Koplak,Artem Talantsev,Yuan Lu,Abbass Hamadeh,Philipp Pirro,Thomas Hauet,R. B. Morgunov,Stéphane Mangin +7 more
TL;DR: In this paper, the applied field temperature (H-T) magnetization switching diagram has been constructed by extracting the different switching fields as a function of temperature, which can be well explained by considering the competition between energy barrier of layer's magnetization reversal, interlayer exchange coupling, and Zeeman energy.
References
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Journal ArticleDOI
A perpendicular-anisotropy CoFeB–MgO magnetic tunnel junction
Shoji Ikeda,Katsuya Miura,Katsuya Miura,H. Yamamoto,H. Yamamoto,K. Mizunuma,Huadong Gan,M. Endo,Shun Kanai,Jun Hayakawa,Fumihiro Matsukura,Hideo Ohno +11 more
TL;DR: Inter interfacial perpendicular anisotropy between the ferromagnetic electrodes and the tunnel barrier of the MTJ is used by employing the material combination of CoFeB-MgO, a system widely adopted to produce a giant tunnel magnetoresistance ratio in MTJs with in-plane an isotropy.
Journal ArticleDOI
Giant room-temperature magnetoresistance in single-crystal Fe/MgO/Fe magnetic tunnel junctions
TL;DR: A giant MR ratio up to 180% at room temperature in single-crystal Fe/MgO/Fe MTJs is reported, indicating that coherency of wave functions is conserved across the tunnel barrier.
Journal ArticleDOI
Giant tunnelling magnetoresistance at room temperature with MgO (100) tunnel barriers
Stuart S. P. Parkin,Christian Kaiser,Alex Panchula,Philip M. Rice,Brian M. Hughes,Mahesh G. Samant,See-Hun Yang +6 more
TL;DR: Sputter-deposited polycrystalline MTJs grown on an amorphous underlayer, but with highly oriented MgO tunnel barriers and CoFe electrodes, exhibit TMR values of up to ∼220% at room temperature and ∼300% at low temperatures, which will accelerate the development of new families of spintronic devices.
Journal ArticleDOI
230% room temperature magnetoresistance in CoFeB/MgO/CoFeB magnetic tunnel junctions
David D. Djayaprawira,K. Tsunekawa,Motonobu Nagai,H. Maehara,Shinji Yamagata,Naoki Watanabe,Shinji Yuasa,Koji Ando +7 more
TL;DR: The magnetoresistance ratio of 230% at room temperature is reported in spin-valve type magnetic tunnel junctions using MgO barrier layer and amorphous CoFeB ferromagnetic electrodes fabricated on thermally oxidized Si substrates.
Journal ArticleDOI
Systematic variation of the strength and oscillation period of indirect magnetic exchange coupling through the 3d, 4d, and 5d transition metals.
TL;DR: The exchange-coupling strength is found to increase systematically from the 5d to 4d to 3d metals and exponentially with increasing number of d electrons along each period.