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Elastic behavior of neodymium based manganites
1Department of Physics, Osmania University, Hyderabad, India.
Ultrasonics
|March 2, 2012
Summary
Elastic properties of Nd(0.67)A(0.33)MnO(3) manganites, where A=Ca, Sr, Ba, Pb, were studied. Elastic parameters and Debye temperature increase with dopant ionic radii, showing anomalies near magnetic transitions.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Solid State Chemistry
Background:
- Manganite systems exhibit complex magnetic and electronic properties.
- Understanding elastic behavior is crucial for characterizing phase transitions.
Purpose of the Study:
- To investigate the elastic properties of Nd(0.67)A(0.33)MnO(3) (A=Ca, Sr, Ba, Pb) system.
- To correlate elastic parameters with dopant ionic radii and magnetic transitions.
Main Methods:
- Sol-gel synthesis for sample preparation.
- X-ray diffraction for structural characterization.
- Pulse transmission technique for ultrasonic velocity measurements (100-300K).
Main Results:
- Elastic parameters and Debye temperature increase with increasing ionic radii of the dopant ion (A).
- Anomalies in longitudinal and transverse velocities observed near ferro-to-paramagnetic transition (T(C)).
- Nd(0.67)Ca(0.33)MnO(3) shows an additional transition at charge ordering temperature (T(co)).
Conclusions:
- Elastic properties are significantly influenced by the ionic radii of the dopant.
- Elastic anomalies are linked to magnetic and charge ordering transitions.
- Mean field theory provides a framework for explaining observed elastic anomalies.
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