Browsing by Author "Pennycook, Stephen J."

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Atomically Resolved Mapping of Polarization and Electric Fields Across Ferroelectric/Oxide Interfaces by Z-contrast Imaging
(2011-06-03)
Chang, Hye Jung
;
Kalinin, Sergei V.
;
Morozovska, Anna N.
;
Huijben, Mark
;
Chu, Ying-Hao
Direct atomic displacement mapping at ferroelectric interfaces by aberration corrected scanning transmission electron microscopy (STEM) (a-STEM image, b-corresponding displacement profile) is combined with the Landau-Ginsburg-Devonshire theory to obtain the complete interface electrostatics in real space, including separate estimates for the polarization and intrinsic interface charge contributions.
Interface dipole between two metallic oxides caused by localized oxygen vacancies
(2012-10-11)
Borisevich, Albina Y.
;
Lupini, Andrew R.
;
He, Jun
;
Eliseev, Eugene A.
;
Morozovska, Anna N.
Oxygen vacancies are increasingly recognized to play a role in phenomena observed at transition-metal oxide interfaces. Here, we report a study of SrRuO3 and La0.7Sr0.3MnO3 interfaces using a combination of quantitative aberration-corrected scanning transmission electron microscopy, electron energy-loss spectroscopy, and density functional calculations. Cation displacements are observed at the interface, indicative of a dipolelike electric field even though both materials are nominally metallic. The observed displacements are reproduced by theory if O vacancies are present in the near-interface La0.7Sr0.3MnO3 layers. The results suggest that atomic-scale structural mapping can serve as a quantitative indicator of the presence of O vacancies at interfaces.