Giant Orbital Anisotropy with Strong Spin–Orbit Coupling Established at the Pseudomorphic Interface of the Co/Pd Superlattice

Sanghoon Kim, Sachin Pathak, Sonny H. Rhim, Jongin Cha, Soyoung Jekal, Soon Cheol Hong, Hyun Hwi Lee, Sung Hun Park, Han Koo Lee, Jae Hoon Park, Soogil Lee, Hans Georg Steinrück, Apurva Mehta, Shan X. Wang, Jongill Hong

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Orbital anisotropy at interfaces in magnetic heterostructures has been key to pioneering spin–orbit-related phenomena. However, modulating the interface's electronic structure to make it abnormally asymmetric has been challenging because of lack of appropriate methods. Here, the authors report that low-energy proton irradiation achieves a strong level of inversion asymmetry and unusual strain at interfaces in [Co/Pd] superlattices through nondestructive, selective removal of oxygen from Co3O4/Pd superlattices during irradiation. Structural investigations corroborate that progressive reduction of Co3O4 into Co establishes pseudomorphic growth with sharp interfaces and atypically large tensile stress. The normal component of orbital to spin magnetic moment at the interface is the largest among those observed in layered Co systems, which is associated with giant orbital anisotropy theoretically confirmed, and resulting very large interfacial magnetic anisotropy is observed. All results attribute not only to giant orbital anisotropy but to enhanced interfacial spin–orbit coupling owing to the pseudomorphic nature at the interface. They are strongly supported by the observation of reversal of polarity of temperature-dependent Anomalous Hall signal, a signature of Berry phase. This work suggests that establishing both giant orbital anisotropy and strong spin–orbit coupling at the interface is key to exploring spintronic devices with new functionalities.

Original languageEnglish
Article number2201749
JournalAdvanced Science
Issue number24
Publication statusPublished - 2022 Aug 25

Bibliographical note

Funding Information:
S.K., S.P., S.H.R. contributed equally to this work. This work was supported by the Creative Materials Discovery Program (2015M3D1A1070465) and by the Program (2019R1A2C2002960) and (2022M3F3A2A01073562) through the National Research Foundation (NRF) funded by the Korea government (MSIT). One of the authors (S.P.) would like to acknowledge the Yonsei University Research Fund (Post Doc. Researcher Supporting Program) of 2017 (project no.: 2017‐12‐0198).

Publisher Copyright:
© 2022 The Authors. Advanced Science published by Wiley-VCH GmbH.

All Science Journal Classification (ASJC) codes

  • Medicine (miscellaneous)
  • Chemical Engineering(all)
  • Materials Science(all)
  • Biochemistry, Genetics and Molecular Biology (miscellaneous)
  • Engineering(all)
  • Physics and Astronomy(all)


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