Naturally Oxidized FeCo as a Magnetic Coupling Layer for Electrically Isolated Read/Write Paths in mLogic

Recently, a nonvolatile, low power circuit scheme based on current-induced domain wall motion and perpendicular magnetic tunnel junctions known as mLogic has been proposed that requires electrically isolated, magnetically coupled read and write paths. Here, we suggest naturally oxidized FeCo for the magnetic coupling layer. Relevant properties of the FeCo-oxide were evaluated by a preliminary investigation of [FeCo/FeCo-Oxide]N artificial superlattices. It is found that FeCo thin films form an insulating 11 Å passivating oxide layer with a magnetization of 500 emu/cc. Experimental measurements show that FeCo-oxide can couple two perpendicular FeCoB layers with a coupling strength greater than 0.35 ergs/cm2.

[1]  A. Vredenberg,et al.  On the initial oxidation of iron: Quantification of growth kinetics by the coupled-currents approach , 1997 .

[2]  H. Ohno,et al.  Transmission electron microscopy study on the effect of various capping layers on CoFeB/MgO/CoFeB pseudo spin valves annealed at different temperatures , 2012 .

[3]  Habraken,et al.  Thin oxide film growth on Fe(100). , 1992, Physical review letters.

[4]  Andrew G. Glen,et al.  APPL , 2001 .

[5]  Jian-Gang Zhu,et al.  Optimization of Ta thickness for perpendicular magnetic tunnel junction applications in the MgO-FeCoB-Ta system , 2012 .

[6]  W J Gallagher,et al.  Demonstration of Ultralow Bit Error Rates for Spin-Torque Magnetic Random-Access Memory With Perpendicular Magnetic Anisotropy , 2011, IEEE Magnetics Letters.

[7]  Lawrence T. Pileggi,et al.  mLogic: Ultra-low voltage non-volatile logic circuits using STT-MTJ devices , 2012, DAC Design Automation Conference 2012.

[8]  H. Ohno,et al.  A perpendicular-anisotropy CoFeB-MgO magnetic tunnel junction. , 2010, Nature materials.

[9]  G. Beach,et al.  Co-Fe metal/native-oxide multilayers: a new direction in soft magnetic thin film design I. Quasi-static properties and dynamic response , 2005, IEEE Transactions on Magnetics.

[10]  H. Ohno,et al.  Dependence of magnetic anisotropy on MgO thickness and buffer layer in Co20Fe60B20-MgO structure , 2011 .

[11]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[12]  A. Stephenson.  Magnetic oxides , 1975, Nature.

[13]  L. Pileggi,et al.  Novel STT-MTJ Device Enabling All-Metallic Logic Circuits , 2012, IEEE Transactions on Magnetics.

[14]  Seung H. Kang,et al.  Development of Embedded STT-MRAM for Mobile System-on-Chips , 2011, IEEE Transactions on Magnetics.