TY - JOUR
KW - Temperature
KW - Defects
KW - Electric fields
KW - Iron compounds
KW - Visualization
KW - Bismuth compounds
KW - Calcium compounds
KW - Activation barriers
KW - Collective dynamics
KW - Collective motions
KW - Crystalline solids
KW - Direct observations
KW - Electric field induced
KW - Future applications
KW - Oxide electrolytes
KW - Oxygen vacancies
AU - J.S Lim
AU - J.H Lee
AU - H.-S Park
AU - R Gao
AU - T.Y Koo
AU - L.W Martin
AU - Ramamoorthy Ramesh
AU - C.-H Yang
AB - The ultrafast motion of oxygen vacancies in solids is crucial for various future applications, such as oxide electrolytes. Visualization and quantification can offer unforeseen opportunities to probe the collective dynamics of defects in crystalline solids, but little research has been conducted on oxygen vacancy electromigration using these approaches. Here, we visualize electric-field-induced creation and propagation of oxygen-vacancy-rich and -poor competing phases and their interface with optical contrast in Ca-substituted BiFeO3 that contains a high density of mobile oxygen vacancies. We quantitatively determined the drift velocity of collective migration to be on the order of 100 μm s−1 with an activation barrier of 0.79 eV, indicating a significantly large ionic mobility of 2 × 10−6 cm2 s−1 V−1 at a remarkably low temperature of 390 °C. In addition, visualization enables direct observation of fluidic behavior, such as the enhancement of conduction at channel edges, which results in U-shaped viscous propagation of the phase boundary and turbulence under a reverse electric field. All of these results provide new insights into the collective motion of defects. © 2018, The Author(s).
BT - NPG Asia Materials
DO - 10.1038/s41427-018-0087-5
LA - eng
M1 - 9
N1 - cited By 3
N2 - The ultrafast motion of oxygen vacancies in solids is crucial for various future applications, such as oxide electrolytes. Visualization and quantification can offer unforeseen opportunities to probe the collective dynamics of defects in crystalline solids, but little research has been conducted on oxygen vacancy electromigration using these approaches. Here, we visualize electric-field-induced creation and propagation of oxygen-vacancy-rich and -poor competing phases and their interface with optical contrast in Ca-substituted BiFeO3 that contains a high density of mobile oxygen vacancies. We quantitatively determined the drift velocity of collective migration to be on the order of 100 μm s−1 with an activation barrier of 0.79 eV, indicating a significantly large ionic mobility of 2 × 10−6 cm2 s−1 V−1 at a remarkably low temperature of 390 °C. In addition, visualization enables direct observation of fluidic behavior, such as the enhancement of conduction at channel edges, which results in U-shaped viscous propagation of the phase boundary and turbulence under a reverse electric field. All of these results provide new insights into the collective motion of defects. © 2018, The Author(s).
PB - Nature Publishing Group
PY - 2018
SP - 943
EP - 955
T2 - NPG Asia Materials
TI - Ultrafast collective oxygen-vacancy flow in Ca-doped BiFeO3
VL - 10
SN - 18844049
ER -