Structural Phase Transitions to 2D and 3D Oxygen Vacancy Patterns in a Perovskite Film Induced by Electrical and Mechanical Nanoprobing

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Abstract

Oxygen vacancy migration and ordering in perovskite oxides enable manipulation of material properties through changes in the cation oxidation state and the crystal lattice. In thin-films, oxygen vacancies conventionally order into equally spaced planes. Here, it is shown that the planar 2D symmetry is broken if a mechanical nanoprobe restricts the chemical lattice expansion that the vacancies generate. Using in situ scanning transmission electron microscopy, a transition from a perovskite structure to a 3D vacancy-ordered phase in an epitaxial La2/3Sr1/3MnO3-delta film during voltage pulsing under local mechanical straining is imaged. The never-before-seen ordering pattern consists of a complex network of distorted oxygen tetrahedra, pentahedra, and octahedra that, together, produce a corrugated atomic structure with lattice constants varying between 3.5 and 4.6 angstrom. The giant lattice distortions respond sensitively to strain variations, offering prospects for non-volatile nanoscale physical property control driven by voltage and gated by strain.

Original languageEnglish
Article number2006273
Number of pages9
JournalSmall
DOIs
Publication statusPublished - 16 Feb 2021
MoE publication typeA1 Journal article-refereed

Keywords

  • electric&#8208
  • field control of magnetism
  • mechanical nanoprobing
  • oxygen vacancy ordering
  • perovskite oxide
  • structural phase transition
  • transmission electron microscopy

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