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Sculpting Nanoscale Functional Channels in Complex Oxides Using Energetic Ions and Electrons.
- Source :
-
ACS applied materials & interfaces [ACS Appl Mater Interfaces] 2018 May 16; Vol. 10 (19), pp. 16731-16738. Date of Electronic Publication: 2018 May 07. - Publication Year :
- 2018
-
Abstract
- The formation of metastable phases has attracted significant attention because of their unique properties and potential functionalities. In the present study, we demonstrate the phase conversion of energetic-ion-induced amorphous nanochannels/tracks into a metastable defect fluorite in A <subscript>2</subscript> B <subscript>2</subscript> O <subscript>7</subscript> structured complex oxides by electron irradiation. Through in situ electron irradiation experiments in a scanning transmission electron microscope, we observe electron-induced epitaxial crystallization of the amorphous nanochannels in Yb <subscript>2</subscript> Ti <subscript>2</subscript> O <subscript>7</subscript> into the defect fluorite. This energetic-electron-induced phase transformation is attributed to the coupled effect of ionization-induced electronic excitations and local heating, along with subthreshold elastic energy transfers. We also show the role of ionic radii of A-site cations (A = Yb, Gd, and Sm) and B-site cations (Ti and Zr) in facilitating the electron-beam-induced crystallization of the amorphous phase to the defect-fluorite structure. The formation of the defect-fluorite structure is eased by the decrease in the difference between ionic radii of A- and B-site cations in the lattice. Molecular dynamics simulations of thermal annealing of the amorphous phase nanochannels in A <subscript>2</subscript> B <subscript>2</subscript> O <subscript>7</subscript> draw parallels to the electron-irradiation-induced crystallization and confirm the role of ionic radii in lowering the barrier for crystallization. These results suggest that employing guided electron irradiation with atomic precision is a useful technique for selected area phase formation in nanoscale printed devices.
Details
- Language :
- English
- ISSN :
- 1944-8252
- Volume :
- 10
- Issue :
- 19
- Database :
- MEDLINE
- Journal :
- ACS applied materials & interfaces
- Publication Type :
- Academic Journal
- Accession number :
- 29697252
- Full Text :
- https://doi.org/10.1021/acsami.8b02326