Related Experiment Video
Updated: Mar 19, 2026
04:51
Comparison of Two Different Synthesis Methods of Single Crystals of Superconducting Uranium Ditelluride
Published on: July 8, 2021
3.2K
Phase Transformations in the High-Tc Superconducting Compounds, Ba2RCu3O7-δ (R = Nd, Sm, Gd, Y, Ho, and Er)
Summary
The structural phase transformation in high-temperature superconductors (Ba2RCu3O7-δ) depends on lanthanide ionic radius. Smaller ionic radii stabilize the orthorhombic phase, influencing superconducting properties and oxygen content.
Area of Science:
- Materials Science
- Solid State Physics
- Superconductivity
Background:
- High-temperature superconductors (HTS) like Ba2RCu3O7-δ exhibit structural phase transitions.
- The oxygen stoichiometry (δ) significantly impacts the properties of these materials.
- Lanthanide (R) substitution introduces variations in ionic radius and electronic structure.
Purpose of the Study:
- Investigate the phase transformation between orthorhombic and tetragonal structures in Ba2RCu3O7-δ superconductors.
- Determine the influence of lanthanide ionic radius on structural stability and superconducting properties.
- Correlate structural transitions with oxygen ordering and stoichiometry.
Main Methods:
- X-ray diffraction (XRD) for structural analysis.
- Differential thermal analysis/thermogravimetric analysis (DTA/TGA) for thermal properties.
- Electron diffraction for detailed structural characterization.
Main Results:
- A superlattice cell (a'=2a) due to oxygen ordering was observed for smaller ionic radius lanthanides (Y, Ho, Er).
- Larger ionic radius lanthanides (Nd, Sm, Gd) did not exhibit this superlattice.
- Phase transition temperatures, oxygen stoichiometry, and T c plateaus correlate with lanthanide ionic radius.
Conclusions:
- Smaller ionic radius lanthanides stabilize the orthorhombic phase to higher temperatures and lower oxygen content.
- Superconducting transition temperature (T c) is less sensitive to oxygen content for smaller ionic radius materials.
- The observed trends can be explained by a quasi-chemical approximation (QCA) considering strain effects on oxygen ordering.
Keywords:
ac magnetic susceptibilityorthorhombic/tetragonal transformationoxygen orderingphase transformation of Ba2RCu3O7−δ (R=lanthanides)strain effect on phase transitiontransition temperatureMore Related Videos
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