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Published on: April 14, 2020
Quadrupolar ordering in LaMnO3 revealed from scattering data and geometric modeling.
A Sartbaeva1, S A Wells, M F Thorpe
1Department of Physics and Astronomy, Arizona State University, Tempe, Arizona 85287-1504, USA.
Physical Review Letters
|November 13, 2007
Summary
Quadrupolar distortions in materials are common but often hidden from average structures. This study reveals a first-order phase transition in LaMnO3, with persistent distortions above the transition temperature.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Crystallography
Background:
- Strongly correlated materials often exhibit quadrupolar (Jahn-Teller) distortions in local octahedral units.
- These local distortions are frequently missed in crystallographic average structures, posing a challenge for understanding material properties.
- Quadrupolar ordering significantly influences the properties of materials like manganites and cuprates.
Purpose of the Study:
- To investigate the nature of local atomic structure and quadrupolar order in strongly correlated materials.
- To resolve the long-standing problem of disorder in structures with local distortions.
- To characterize the quadrupolar order parameter and its behavior during phase transitions.
Main Methods:
- Utilizing high-resolution scattering data.
- Employing novel geometrical modeling techniques.
- Combining local structure probes with average structure analysis.
Main Results:
- A detailed picture of the local atomic structure was obtained.
- The quadrupolar order parameter associated with distorted octahedra was successfully extracted.
- In LaMnO3, quadrupoles exhibit a strong first-order phase transition at 730 K.
- A non-zero quadrupolar order parameter persists in the high-temperature phase of LaMnO3.
Conclusions:
- The study provides a comprehensive understanding of local atomic structure and quadrupolar ordering.
- Novel methods allow for the extraction of the quadrupolar order parameter, clarifying structural disorder.
- The persistence of quadrupolar order above the transition temperature in LaMnO3 offers new insights into strongly correlated materials.
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