Skip to main content
SpringerLink
Log in

Origin of Interfacial Magnetic Anisotropy in Ta/CoFeB/MgO and Pt/CoFeB/MgO Multilayer Thin Film Stacks

  • Letter
  • Published:
Journal of Superconductivity and Novel Magnetism Aims and scope Submit manuscript

Abstract

Interfacial perpendicular magnetic anisotropy (PMA) in Pt/Co40Fe40B20/MgO and Ta/Co40Fe40B20/MgO multilayer structures has been researched at various CoFeB layer thicknesses. Magneto-optical Kerr effect (MOKE) and vibrating sample magnetometer (VSM) measurements show that while strong PMA is achieved in Ta/Co40Fe40B20/MgO structure for the thickness of Co40Fe40B20 range from 0.5 to 1.0 nm, a very weak PMA is observed in Pt/Co40Fe40B20/MgO film stack for the same Co40Fe40B20 thicknesses. Based on the experimental results, the interfacial anisotropy energy in Ta/Co40Fe40B20/MgO (1.17 erg/cm2) was found to be almost 2.5× larger than that in Pt/Co40Fe40B20/MgO (0.43 erg/cm2). It is accepted that the PMA comes from the seed/ferromagnetic and ferromagnetic/oxide layer interfaces. Thus, the origin of interfacial magnetic anisotropy can be hybridization and/or crystallinity properties at the interfaces in Ta- and Pt-seeded stacks. While the PMA is strong in Pt/Co/MgO structure, it becomes in-plane in Fe-rich Pt/CoFeB/MgO structure. It is deduced that hybridization between 3d-5d (Co-Pt) orbitals is more dominant in Pt/CoFeB interface than 2p-3d (O-Fe) hybridization at CoFeB/MgO interface in Pt-seeded stacks. In addition, the crystallinity was studied by performing high-resolution x-ray diffraction (HR-XRD) technique. The crystal orientations of Ta and Pt are found as (002) and (111), respectively. The ferromagnetic layer might be induced out-of-plane orientation in Ta-seeded stack due to observing highly crystallized MgO (001). Thus, another reason for in-plane magnetic anisotropy in Pt/Co40Fe40B20/MgO might be the absence of MgO crystallization because Pt is crystallized fcc (111) orientation.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5

Similar content being viewed by others

References

  1. Iwasaki, S.: Perpendicular magnetic recording. IEEE Transactions on Magnetics 16, 71–76 (1980). https://doi.org/10.1109/TMAG.1980.1060546

    Article  ADS  Google Scholar 

  2. Moodera, J.S., Kinder, L.R., Wong, T.M., Meservey, R.: Large Magnetoresistance at room temperature in ferromagnetic thin film tunnel junctions. Phys. Rev. Lett. 74, 3273–3276 (1995)

    Article  ADS  Google Scholar 

  3. Grundy, P.J.: Thin film magnetic recording media. J. Phys. D. Appl. Phys. 31, 2975–2990 (1998)

    Article  ADS  Google Scholar 

  4. Parkin, S., Xin, J., Kaiser, C., Panchula, A., Roche, K., Samant, M.: Magnetically engineered spintronic sensors and memory. Proc. IEEE. 91, 661–680 (2003). https://doi.org/10.1109/JPROC.2003.811807

    Article  Google Scholar 

  5. Mathon, J., Umerski, A.: Theory of tunneling magnetoresistance of an epitaxial Fe/MgO/Fe(001) junction. Phys. Rev. B. 63, 220403 (2001)

    Article  ADS  Google Scholar 

  6. Nishimura, N., Hirai, T., Koganei, A., Ikeda, T., Okano, K., Sekiguchi, Y., Osada, Y.: Magnetic tunnel junction device with perpendicular magnetization films for high-density magnetic random access memory. J. Appl. Phys. 91, 5246–5249 (2002). https://doi.org/10.1063/1.1459605

    Article  ADS  Google Scholar 

  7. Parkin, S.S.P., Kaiser, C., Panchula, A., Rice, P.M., Hughes, B., Samant, M., Yang, S.H.: Giant tunnelling magnetoresistance at room temperature with MgO (100) tunnel barriers. Nat. Mater. 3, 862–867 (2004)

    Article  ADS  Google Scholar 

  8. Djayaprawira, D.D., Tsunekawa, K., Nagai, M., et al.: 230% room-temperature magnetoresistance in CoFeB∕MgO∕CoFeB magnetic tunnel junctions. Appl. Phys. Lett. 86, 092502 (2005). https://doi.org/10.1063/1.1871344

    Article  ADS  Google Scholar 

  9. Wang, K.L., Alzate, J.G., Khalili Amiri, P.: Low-power non-volatile spintronic memory: STT-RAM and beyond. J. Phys. D. Appl. Phys. 46, 074003 (2013). https://doi.org/10.1088/0022-3727/46/7/074003

    Article  ADS  Google Scholar 

  10. Chiba, D., Yamanouchi, M., Matsukura, F., Ohno, H.: Electrical manipulation of magnetization reversal in a ferromagnetic semiconductor. Science. 301, 943–945 (2003). https://doi.org/10.1126/science.1086608

    Article  ADS  Google Scholar 

  11. Weisheit, M., Fähler, S., Marty, A., Souche, Y., Poinsignon, C., Givord, D.: Electric field-induced modification of magnetism in thin-film ferromagnets. Science. 315, 349–351 (2007). https://doi.org/10.1126/science.1136629

    Article  ADS  Google Scholar 

  12. G, Y., Upadhyaya, P., Fan, Y., et al.: Switching of perpendicular magnetization by spin–orbit torques in the absence of external magnetic fields. Nat. Nanotechnol. 9, 548–554 (2014). https://doi.org/10.1038/nnano.2014.94 http://www.nature.com/nnano/journal/v9/n7/abs/nnano.2014.94.html#supplementary-information

    Article  ADS  Google Scholar 

  13. Kaidatzis, A., Bran, C., Psycharis, V., Vázquez, M., García-Martín, J.M., Niarchos, D.: Tailoring the magnetic anisotropy of CoFeB/MgO stacks onto W with a Ta buffer layer. Appl. Phys. Lett. 106, 262401 (2015). https://doi.org/10.1063/1.4923272

    Article  ADS  Google Scholar 

  14. Liu, T., Cai, J.W., Sun, L.: Large enhanced perpendicular magnetic anisotropy in CoFeB/MgO system with the typical Ta buffer replaced by an Hf layer. AIP Adv. 2, 032151 (2012). https://doi.org/10.1063/1.4748337

    Article  ADS  Google Scholar 

  15. Peng, S., Wang, M., Yang, H., Zeng, L., Nan, J., Zhou, J., Zhang, Y., Hallal, A., Chshiev, M., Wang, K.L., Zhang, Q., Zhao, W.: Origin of interfacial perpendicular magnetic anisotropy in MgO/CoFe/metallic capping layer structures. Sci. Rep. 5, 18173 (2015). https://doi.org/10.1038/srep18173 http://www.nature.com/articles/srep18173#supplementary-information

    Article  ADS  Google Scholar 

  16. Liu, T., Zhang, Y., Cai, J.W., Pan, H.Y.: Thermally robust Mo/CoFeB/MgO trilayers with strong perpendicular magnetic anisotropy. Sci. Rep. 4, 5895 (2014). https://doi.org/10.1038/srep05895

    Article  ADS  Google Scholar 

  17. Gweon, H.K., Yun, S.J., Lim, S.H.: A very large perpendicular magnetic anisotropy in Pt/Co/MgO trilayers fabricated by controlling the MgO sputtering power and its thickness. Sci. Rep. 8, 1266 (2018). https://doi.org/10.1038/s41598-018-19656-9

    Article  ADS  Google Scholar 

  18. Tudu, B., Tian, K., Tiwari, A.: Effect of composition and thickness on the perpendicular magnetic anisotropy of (Co/Pd) multilayers. Sensors (Basel). 17, (2017). https://doi.org/10.3390/s17122743

    Article  Google Scholar 

  19. Peng, S., Zhao, W., Qiao, J., Su, L., Zhou, J., Yang, H., Zhang, Q., Zhang, Y., Grezes, C., Amiri, P.K., Wang, K.L.: Giant interfacial perpendicular magnetic anisotropy in MgO/CoFe/capping layer structures. Appl. Phys. Lett. 110, 072403 (2017). https://doi.org/10.1063/1.4976517

    Article  ADS  Google Scholar 

  20. Cui, B., Song, C., Wang, G.Y., Wang, Y.Y., Zeng, F., Pan, F.: Perpendicular magnetic anisotropy in CoFeB/X (X=MgO, Ta, W, Ti, and Pt) multilayers. J. Alloys Compd. 559, 112–115 (2013). https://doi.org/10.1016/j.jallcom.2013.01.093

    Article  Google Scholar 

  21. Akyol, M., Yu, G., Alzate, J.G., et al.: Current-induced spin-orbit torque switching of perpendicularly magnetized Hf|CoFeB|MgO and Hf|CoFeB|TaOxstructures. Appl. Phys. Lett. 106, 162409 (2015). https://doi.org/10.1063/1.4919108

    Article  ADS  Google Scholar 

  22. Akyol, M., W Jiang, G.Y., et al.: Effect of heavy metal layer thickness on spin-orbit torque and current-induced switching in Hf|CoFeB|MgO structures. Appl. Phys. Lett. 109, 022403 (2016). https://doi.org/10.1063/1.4958295

    Article  ADS  Google Scholar 

  23. Li, M., Lu, J., Akyol, M., et al.: The impact of Hf layer thickness on the perpendicular magnetic anisotropy in Hf/CoFeB/MgO/Ta films. J. Alloys Compd. 694, 76–81 (2017). https://doi.org/10.1016/j.jallcom.2016.09.309

    Article  Google Scholar 

  24. Ikeda, S., Miura, K., Yamamoto, H., Mizunuma, K., Gan, H.D., Endo, M., Kanai, S., Hayakawa, J., Matsukura, F., Ohno, H.: A perpendicular-anisotropy CoFeB–MgO magnetic tunnel junction. Nat. Mater. 9, 721–724 (2010)

    Article  ADS  Google Scholar 

  25. Worledge, D.C., Hu, G., Abraham, D.W., et al.: Spin torque switching of perpendicular Ta∣CoFeB∣MgO-based magnetic tunnel junctions. Appl. Phys. Lett. 98, 022501 (2011). https://doi.org/10.1063/1.3536482

    Article  ADS  Google Scholar 

  26. Lee, S.-C., Kim, K.-S., Lee, S.-H., et al.: Effect of Fe–O distance on magnetocrystalline anisotropy energy at the Fe/MgO(001) interface. J. Appl. Phys. 113, 023914 (2013). https://doi.org/10.1063/1.4775604

    Article  ADS  Google Scholar 

  27. Yang, H.X., Chshiev, M., Dieny, B., Lee, J.H., Manchon, A., KH, S.: First-principles investigation of the very large perpendicular magnetic anisotropy at Fe|MgO and Co|MgO interfaces. Phys. Rev. B. 84, 054401 (2011)

    Article  ADS  Google Scholar 

  28. Odkhuu, D., Yun, W.S., Rhim, S.H., Hong, S.C.: Theory of perpendicular magnetocrystalline anisotropy in Fe/MgO (001). J. Magn. Magn. Mater. 414, 126–131 (2016). https://doi.org/10.1016/j.jmmm.2016.04.027

    Article  ADS  Google Scholar 

  29. Sanghoon, K., Seung-heon Chris, B., Mio, I., et al.: Contributions of Co and Fe orbitals to perpendicular magnetic anisotropy of MgO/CoFeB bilayers with Ta, W, IrMn, and Ti underlayers. Appl. Phys. Express. 10, 073006 (2017). https://doi.org/10.7567/APEX.10.073006

    Article  ADS  Google Scholar 

  30. Baumann, S., Donati, F., Stepanow, S., et al.: Origin of perpendicular magnetic anisotropy and large orbital moment in Fe atoms on MgO. Phys. Rev. Lett. 115, 237202 (2015). https://doi.org/10.1103/PhysRevLett.115.237202

    Article  ADS  Google Scholar 

  31. Okabayashi, J., Koo, J.W., Sukegawa, H., Mitani, S., Takagi, Y., Yokoyama, T.: Perpendicular magnetic anisotropy at the interface between ultrathin Fe film and MgO studied by angular-dependent x-ray magnetic circular dichroism. Appl. Phys. Lett. 105, 122408 (2014). https://doi.org/10.1063/1.4896290

    Article  ADS  Google Scholar 

Download references

Acknowledgments

This work was also partially supported by Çukurova University (Adana/Turkey) and University of California Los Angeles (Los Angeles/USA) in terms of usage of facilities in Device Research Laboratory and Central Research Laboratory. The author thanks Dr. Kang L. Wang, Dr. Pedram K. Amiri, and Dr. Ahmet Ekicibil for their valuable discussion.

Funding

This work was partially supported by Adana Science and Technology University (Adana/Turkey) under the project number of 17103024.

Author information

Authors and Affiliations

  1. Department of Materials Engineering, Adana Science and Technology University, 01250, Adana, Turkey

    Mustafa Akyol

Authors
  1. Mustafa Akyol
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Mustafa Akyol.

Additional information

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Akyol, M. Origin of Interfacial Magnetic Anisotropy in Ta/CoFeB/MgO and Pt/CoFeB/MgO Multilayer Thin Film Stacks. J Supercond Nov Magn 32, 457–462 (2019). https://doi.org/10.1007/s10948-019-5005-8

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10948-019-5005-8

Keywords

Search

Navigation