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Science China Technological Sciences

, Volume 62, Issue 11, pp 2009–2013 | Cite as

Large lattice mismatch induced perpendicular magnetic anisotropy and perpendicular exchange bias in CoPt/FeMn bilayer films

  • ChunJiao Pan
  • TengHua Gao
  • Nobuhide Itogawa
  • Takashi Harumoto
  • ZhengJun Zhang
  • Yoshio Nakamura
  • Ji ShiEmail author
Article
  • 18 Downloads

Abstract

Perpendicular magnetic anisotropy and perpendicular exchange bias of CoPt/FeMn bilayers fabricated by dc magnetron sputtering were investigated in this work. Magnetic anisotropy, showing strong dependence on thickness of CoPt layer, changes from perpendicular magnetic anisotropy (PMA) into in-plane magnetic anisotropy when CoPt layer is thicker than 4.5 nm. The evolution of internal stress with thickness, from tensile to compressive, has been analyzed by sin2ψ method using an equal biaxial stress model. Distinctive perpendicular exchange bias (PEB) has been successfully established due to PMA of CoPt and out-of-plane spin component of 3Q-spin-structured FeMn. FeMn thickness dependence of exchange bias field has been systematically investigated.

Keywords

perpendicular magnetic anisotropy perpendicular exchange bias X-ray technique magnetic materials 

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References

  1. 1.
    Phuoc N N, Suzuki T. Perpendicular exchange bias mechanism in FePt/FeMn multilayers. J Appl Phys, 2007, 101: 09E501CrossRefGoogle Scholar
  2. 2.
    van den Brink A, Vermijs G, Solignac A, et al. Field-free magnetization reversal by spin-Hall effect and exchange bias. Nat Commun, 2016, 7: 10854CrossRefGoogle Scholar
  3. 3.
    Zhang W, Han W, Yang S H, et al. Giant facet-dependent spin-orbit torque and spin Hall conductivity in the triangular antiferromagnet IrMn3. Sci Adv, 2016, 2: e1600759CrossRefGoogle Scholar
  4. 4.
    Ma X, Yu G, Razavi S A, et al. Dzyaloshinskii-Moriya interaction across an antiferromagnet-ferromagnet interface. Phys Rev Lett, 2017, 119: 027202CrossRefGoogle Scholar
  5. 5.
    An H, Ando K, Nakamura Y, et al. Formation and perpendicular magnetic coupling of A1 and L10 CoPt in CoPt/TiN films on glass substrate. IEEE Trans Magn, 2018, 55: 1–4CrossRefGoogle Scholar
  6. 6.
    Liu D, Liu X M, Liu G Q, et al. Phase stability and magnetic performance of nanocrystalline Sm-Co supersaturated solid solution. Sci China Tech Sci, 2018, 61: 129–134CrossRefGoogle Scholar
  7. 7.
    Ahn S M, Beach G S D. Crossover between in-plane and perpendicular anisotropy in Ta/CoxFe100-x/MgO films as a function of Co composition. J Appl Phys, 2013, 113: 17C112CrossRefGoogle Scholar
  8. 8.
    Basile F, Poix P. Etude par effect Mössbauer et mesures magnétiques de la solution solide Fe2−2xMg1+xSnxO4. Phys Stat Sol (a), 1976, 35: 153–164CrossRefGoogle Scholar
  9. 9.
    Lisfi A, Williams C M, Nguyen L T, et al. Reorientation of magnetic anisotropy in epitaxial cobalt ferrite thin films. Phys Rev B, 2007, 76: 054405CrossRefGoogle Scholar
  10. 10.
    Niizeki T, Utsumi Y, Aoyama R, et al. Extraordinarily large perpendicular magnetic anisotropy in epitaxially strained cobalt-ferrite CoxFe3−2xO4 (001) (x = 0.75, 1.0) thin films. Appl Phys Lett, 2013, 103: 162407CrossRefGoogle Scholar
  11. 11.
    Numata Y, Itabashi A, Ohtake M, et al. Structural characterization of FePd, FePt, and CoPt alloy thin filmsepitaxially groown on (001) surface of different single-crystal materials. IEEE Trans Magn, 2013, 50: 1–4CrossRefGoogle Scholar
  12. 12.
    Phuoc N N, Chen H Y, Ong C K. Effect of antiferromagnetic thickness on thermal stability of static and dynamic magnetization of NiFe/FeMn multilayers. J Appl Phys, 2013, 113: 063913CrossRefGoogle Scholar
  13. 13.
    Martínez-Boubeta C, Botana A S, Pardo V, et al. Heteroepitaxial growth of MgO(111) thin films on Al2O3 (0001): Evidence of a wurtzite to rocksalt transformation. Phys Rev B, 2012, 86: 041407CrossRefGoogle Scholar
  14. 14.
    Yu Y, Shi J, Nakamura Y. Thickness-dependent perpendicular magnetic anisotropy of CoPt top layer on CoPt/AlN multilayer. IEEE Trans Magn, 2010, 46: 1663–1666CrossRefGoogle Scholar
  15. 15.
    Pan C, Gao T, Harumoto T, et al. Asymmetry in magnetic behavior caused by superposition of unidirectional and four-fold magnetic anisotropies in CoPt/FeMn bilayers. Appl Surf Sci, 2019, 480: 148–153CrossRefGoogle Scholar
  16. 16.
    Guo L, Wang Y, Wang J, et al. Magnetoelastically induced perpendicular magnetic anisotropy and perpendicular exchange bias of CoO/CoPt multilayer films. J Magn Magn Mater, 2015, 394: 349–353CrossRefGoogle Scholar
  17. 17.
    Nogués J, Schuller I K. Exchange bias. J Magn Magn Mater, 1999, 192: 203–232CrossRefGoogle Scholar
  18. 18.
    Zhao X P, Lu J, Mao S W, et al. Spontaneous perpendicular exchange bias effect in L 10-MnGa/FeMn bilayers grown by molecular-beam epitaxy. Appl Phys Lett, 2018, 112: 042403CrossRefGoogle Scholar
  19. 19.
    Lenz K, Zander S, Kuch W. Magnetic proximity effects in antiferromagnet/ferromagnet bilayers: The impact on the Néel temperature. Phys Rev Lett, 2007, 98: 237201CrossRefGoogle Scholar
  20. 20.
    Xi H, White R M, Mao S, et al. Low-frequency dynamic hysteresis in exchange-coupled Ni81Fe19/Ir22Mn78 bilayers. Phys Rev B, 2001, 64: 184416CrossRefGoogle Scholar
  21. 21.
    Bolon B T, Haugen M A, Abin-Fuentes A, et al. Multiple antiferromagnet/ferromagnet interfaces as a probe of grain-size-dependent exchange bias in polycrystalline Co/Fe50Mn50. J Magn Magn Mater, 2007, 309: 54–63CrossRefGoogle Scholar
  22. 22.
    Chang H W, Yuan F T, Chiang M T, et al. Effect of Ta underlayer on magnetic properties of FeMn/NiFe films. Surf Coatings Tech, 2016, 303: 148–153CrossRefGoogle Scholar

Copyright information

© Science China Press and Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • ChunJiao Pan
    • 1
    • 2
  • TengHua Gao
    • 2
    • 3
  • Nobuhide Itogawa
    • 2
  • Takashi Harumoto
    • 2
  • ZhengJun Zhang
    • 1
  • Yoshio Nakamura
    • 2
  • Ji Shi
    • 2
    Email author
  1. 1.School of Materials Science and EngineeringTsinghua UniversityBeijingChina
  2. 2.School of Materials and Chemical TechnologyTokyo Institute of TechnologyTokyoJapan
  3. 3.Department of Applied Physics and Physico-InformaticsKeio UniversityTokyoJapan

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