Journal of Materials Research

Articles

Strain relaxation defects in perovskite oxide superlattices

Meng Gua1, Michael D. Biegalskia2, Hans M. Christena2, Chengyu Songa3, Craig R. Deardena4, Nigel D. Browninga5 p1 and Yayoi Takamuraa6 c1

a1 Department of Chemical Engineering and Materials Science, University of California–Davis, Davis, California 95616

a2 Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831

a3 National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, California 94720

a4 Department of Chemical Engineering and Materials Science, University of California–Davis, Davis, California 95616

a5 Department of Chemical Engineering and Materials Science, University of California–Davis, Davis, California 95616; Department of Molecular and Cellular Biology, University of California–Davis, Davis, California 95616

a6 Department of Chemical Engineering and Materials Science, University of California–Davis, Davis, California 95616

Abstract

This paper reports on the defect structures formed upon strain relaxation in pulsed laser-deposited complex oxide superlattices consisting of the ferromagnetic metal, La0.67Sr0.33MnO3, and the antiferromagnetic insulator, La0.67Sr0.33FeO3. Atomic resolution scanning transmission electron microscopy and electron energy loss spectroscopy were used to characterize the structure and chemistry of the defects. For thinner superlattices, strain relaxation occurs through the formation of 2-D stacking faults, whereas for thicker superlattices, the prolonged thermal exposure during film growth leads to the formation of nanoflowers and cracks/pinholes to reduce the overall strain energy.

(Received September 26 2011)

(Accepted January 24 2012)

Key Words:

  • Scanning transmission electron microscopy (STEM);
  • Electron energy loss spectroscopy (EELS);
  • Defects

Correspondence:

c1 Address all correspondence to this author. e-mail: ytakamura@ucdavis.edu

p1 Current address: Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352

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