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Interfacial Perpendicular Magnetic Anisotropy in Magnetic Tunnel Junctions Comprising CoFeB with FeNiSiB Layers

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Abstract

Controlling ferromagnetic thickness (t) and properties such as saturation magnetization (Ms) and effective magnetic anisotropy constant (Keff) has been regarded as critical for the performance of magnetic tunnel junctions (MTJs) with interfacial perpendicular magnetic anisotropy. Here, we report the effects of hybridizing a CoFeB layer with a FeNiSiB layer as part of a magnetic free layer structure. We deposited thin film stacks by magnetron sputtering on Si wafers with thermal oxides and carried out post-deposition heat treatment at 300 °C for 1 h in a vacuum under a magnetic field. We found that Ms and Keff could be tuned by adding a layer of amorphous FeNiSiB. While the Ms and Keff values were modified, the tunneling magnetoresistance (TMR) ratios of the MTJs were maintained, even though the CoFeB thickness was decreased by half. Moreover, an asymmetric bias voltage dependence of TMR was suppressed in the MTJs with FeNiSiB/CoFeB hybrid free layers due to improvements in the interface quality between the CoFeB/MgO interfaces.

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Acknowledgements

This work was supported in part by the Future Materials Discovery Program through the National Research Foundation of Korea, funded by the Ministry of Science and ICT (Grant No. 2015M3D1A1070465), by the Samsung Electronics’ University R&D program.

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Authors and Affiliations

  1. Department of Materials Science and Engineering, Korea University, Seoul, 02841, Korea

    Do Kyun Kim, Minhyeok Lee & Young Keun Kim

  2. Department of Materials Science and Engineering, Kunsan National University, Kunsan-si, Jeollabuk-do, 54150, Korea

    Junghoon Joo

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  1. Do Kyun Kim
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  2. Minhyeok Lee
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  4. Young Keun Kim
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Correspondence to Young Keun Kim.

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Kim, D.K., Lee, M., Joo, J. et al. Interfacial Perpendicular Magnetic Anisotropy in Magnetic Tunnel Junctions Comprising CoFeB with FeNiSiB Layers. Electron. Mater. Lett. 16, 35–40 (2020). https://doi.org/10.1007/s13391-019-00183-2

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  • DOI: https://doi.org/10.1007/s13391-019-00183-2

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