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Five-dimensional visualization of phase transition in BiNiO3 under high pressure
Yijin Liu1, Junyue Wang2, Masaki Azuma3
1Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
Applied Physics Letters
|April 23, 2014
Summary
Researchers visualized phase transitions in Bismuth Nickel Oxide (BiNiO3) using advanced X-ray tomography. This method reveals nanoscale interface dynamics crucial for understanding colossal negative thermal expansion under pressure.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Crystallography
Background:
- Colossal negative thermal expansion (CNTE) observed in Bismuth Nickel Oxide (BiNiO3) is linked to a pressure-induced phase transition.
- The macroscopic properties of BiNiO3 are significantly influenced by the coexistence and proportion of its low-density and high-density phases.
- Understanding the interface dynamics between these phases is critical for harnessing CNTE effects.
Purpose of the Study:
- To visualize and resolve the mixture of high- and low-pressure phases in BiNiO3 at the nanoscale.
- To investigate the pressure-dependent behavior and interface dynamics of co-existing phases.
- To demonstrate the utility of X-ray Absorption Near Edge Spectroscopy Tomography for studying phase transitions.
Main Methods:
- Application of a novel X-ray Absorption Near Edge Spectroscopy Tomography (XANES-T) method.
- High-resolution (tens of nanometers) imaging of phase distribution as a function of pressure.
- Utilizing charge transfer during the phase transition to differentiate between high- and low-pressure phases.
Main Results:
- Successful visualization of the mixture of high- and low-pressure phases in BiNiO3 with nanoscale resolution.
- Five-dimensional (X, Y, Z, energy, pressure) mapping of phase boundaries and their evolution.
- Demonstration of charge transfer as a sensitive probe for phase identification and imaging.
Conclusions:
- XANES-T provides a powerful high-resolution tool for studying the complex interplay of co-existing phases in materials.
- The nanoscale visualization of phase boundaries offers new insights into the mechanisms driving colossal negative thermal expansion.
- This methodology enables detailed investigation of interface dynamics critical for materials design and application.
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