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Shear strain in Nd0.5Ca0.5MnO3 at high pressures
Anthony Arulraj1, Robert E Dinnebier, Stefan Carlson
1Laboratory of Crystallography, University of Bayreuth, D-95440 Bayreuth, Germany. anthony.arulraj@uni-bayreuth.de
Physical Review Letters
|May 21, 2005
Summary
High-pressure studies reveal shear distortion in rare earth manganites (Nd0.5Ca0.5MnO3) at 15 GPa. This shear strain explains the material's insulating properties under extreme pressure.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Crystallography
Background:
- Rare earth manganites exhibit complex phase transitions.
- Understanding their behavior under pressure is crucial for electronic applications.
Purpose of the Study:
- To investigate the structural response of Nd0.5Ca0.5MnO3 to high pressures.
- To elucidate the relationship between structural distortions and electronic properties.
Main Methods:
- High-pressure X-ray powder diffraction up to 15 GPa.
- Analysis of lattice strain and octahedral distortions.
Main Results:
- Quantifiable shear distortion of MnO6 octahedra observed at high pressures.
- Minimal lattice strain at a crossover pressure (p* ≈ 7 GPa).
- Shear and Jahn-Teller distortions contribute to lattice strain above and below p*, respectively.
Conclusions:
- Increased shear strain with pressure provides a novel mechanism for the insulating behavior of manganites.
- High-pressure structural changes significantly influence the electronic properties of these materials.