Influence of quantum confinement on magnetic properties of Fe/Mo/Fe and Fe/Ta/Fe thin-film systems

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.

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Effect of Ta thickness on the perpendicular magnetic anisotropy in MgO/CoFeB/Ta/[Co/Pd]n structures

Chang

Canizo-Cabrera

Garcı́a-Vázquez

et al. 2013

Journal of Applied Physics

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We studied the effect of a thin Ta layer on the perpendicular magnetic anisotropy (PMA) of composite FM1/Ta/FM2 magnetic structures, where FM1 represents the subsystem MgO/CoFeB, and FM2 denotes a [Co/Pd]6 multilayer. The stack without Ta spacer layer shows no PMA. Once a Ta layer is inserted between the thin CoFeB layer and the [Co/Pd]6 multilayer, PMA is observed. The perpendicular magnetization loops show squareness ratios close to unity, indicating the presence of almost complete perpendicular anisotropy. These hysteresis loops also show sharp switching characteristics, indicating that the MgO/CoFeB bilayer and the [Co/Pd]6 multilayer are ferromagnetically coupled together. The coercive field Hc of the composite structure increases as Ta thickness increases. Our results show that Ta layer is essential for integrating MgO/CoFeB and [Co/Pd]6 into a composite magnetic structure with perpendicular anisotropy.

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Influence of quantum confinement on magnetic properties of Fe/Mo/Fe and Fe/Ta/Fe thin-film systems

Cited by 7 publications

References 18 publications

Interlayer exchange coupling with Ir/(Ru, Mo, or W)/Ir composite spacers in perpendicular synthetic antiferromagnets

Interlayer exchange coupling with Ir/(Ru, Mo, or W)/Ir composite spacers in perpendicular synthetic antiferromagnets

Perpendicular-anisotropy CoFeB-MgO magnetic tunnel junctions with a MgO/CoFeB/Ta/CoFeB/MgO recording structure

Effect of Ta thickness on the perpendicular magnetic anisotropy in MgO/CoFeB/Ta/[Co/Pd]n structures

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