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Title: Contradictory nature of Co doping in ferroelectric BaTi O 3

The growth of Co-substituted BaTiO 3 (BTO) films on Ge(001) substrates by molecular beam epitaxy is demonstrated in this paper. Energy-dispersive x-ray spectroscopy and transmission electron microscopy images confirm the uniform Co distribution. However, no evidence of magnetic ordering is observed in samples grown for Co concentrations between 2% and 40%. Piezoresponse force microscopy measurements show that a 5% Co-substituted BTO sample exhibits ferroelectric behavior. First-principles calculations indicate that while Co atoms couple ferromagnetically in the absence of oxygen vacancies, the occurrence of oxygen vacancies leads to locally antiferromagnetically coupled complexes with relatively strong spin coupling. Finally, the presence of a significant amount of oxygen vacancies is suggested by x-ray photoelectron spectroscopy measurements.
 [1] ;  [1] ;  [2] ;  [1] ;  [3] ;  [3] ;  [3] ;  [1] ;  [4] ;  [5] ;  [6] ;  [1] ;  [4] ;  [3] ;  [5] ;  [1]
  1. Univ. of Texas, Austin, TX (United States). Dept. of Physics
  2. Soochow Univ., Suzhou (China). Dept. of Physics. Jiangsu Key Lab. of Thin Films
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences
  4. Univ. of Texas, Austin, TX (United States). Materials Science and Engineering Program/Mechanical Engineering
  5. Arizona State Univ., Tempe, AZ (United States). Dept. of Physics
  6. IBM Almaden Research Center, San Jose, CA (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725; FA9550-12-10494; 11104194
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 94; Journal Issue: 20; Journal ID: ISSN 2469-9950
American Physical Society (APS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Texas, Austin, TX (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); US Air Force Office of Scientific Research (AFOSR); National Natural Science Foundation of China (NNSFC)
Contributing Orgs:
IBM Almaden Research Center, San Jose, CA (United States); Soochow Univ., Suzhou (China); Arizona State Univ., Tempe, AZ (United States)
Country of Publication:
United States
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ferroelectrics; piezoresponse force microscopy; DFT
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1331837