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Title: Controllable positive exchange bias via redox-driven oxygen migration

We report that ionic transport in metal/oxide heterostructures offers a highly effective means to tailor material properties via modification of the interfacial characteristics. However, direct observation of ionic motion under buried interfaces and demonstration of its correlation with physical properties has been challenging. Using the strong oxygen affinity of gadolinium, we design a model system of Gd xFe 1-x/NiCoO bilayer films, where the oxygen migration is observed and manifested in a controlled positive exchange bias over a relatively small cooling field range. The exchange bias characteristics are shown to be the result of an interfacial layer of elemental nickel and cobalt, a few nanometres in thickness, whose moments are larger than expected from uncompensated NiCoO moments. This interface layer is attributed to a redox-driven oxygen migration from NiCoO to the gadolinium, during growth or soon after. Ultimately, these results demonstrate an effective path to tailoring the interfacial characteristics and interlayer exchange coupling in metal/oxide heterostructures.
ORCiD logo [1] ;  [2] ;  [3] ;  [4] ;  [4] ;  [4] ;  [5] ;  [4] ; ORCiD logo [2]
  1. Univ. of California, Davis, CA (United States). Dept. of Physics; NIST Center for Neutron Research, Gaithersburg, MD (United States)
  2. Univ. of California, Davis, CA (United States)
  3. Univ. of California, Davis, CA (United States); Univ. of Gothenburg (Sweden)
  4. NIST Center for Neutron Research, Gaithersburg, MD (United States)
  5. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS)
Publication Date:
OSTI Identifier:
Grant/Contract Number:
AC02-05CH11231; DMR-1008791; ECCS-1232275; DMR-1543582
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 2041-1723
Nature Publishing Group
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States