Structural phase transition and magnetic-field effect on the modulated structure in GdBaCo2O5+δ (δ < 0.5)
1Department of Materials Science and Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan.
Physical Review Letters
|August 29, 2014
Summary
This study reveals a structural phase transition in GdBaCo2O(5+δ) above its magnetic ordering temperature. A magnetic field induces an incommensurate phase, indicating a novel magnetic-field-driven structural change.
Area of Science:
- Materials Science
- Solid State Physics
- Crystallography
Background:
- Ordered perovskite-type cobaltates exhibit complex structural and magnetic properties.
- Understanding phase transitions is crucial for designing advanced materials.
Purpose of the Study:
- To investigate the high-temperature crystal structures of GdBaCo2O(5+δ) (δ < 0.5).
- To explore the influence of magnetic fields on the structural phase transitions.
Main Methods:
- Transmission electron microscopy (TEM) was employed to study crystal structures.
- Experiments were conducted at elevated temperatures and under applied magnetic fields.
Main Results:
- A first-order structural phase transition was observed above the magnetic ordering temperature.
- The transition occurs between tetragonal (3a(p) × 3a(p)) and orthorhombic (1a(p) × 2a(p)) superstructure phases.
- An incommensurate phase emerged under a magnetic field near the transition temperature.
Conclusions:
- The study demonstrates a magnetic-field-induced structural phase transition in GdBaCo2O(5+δ) without magnetic ordering.
- This finding highlights a unique coupling between magnetic fields and structural dynamics in perovskite cobaltates.
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