Local distortions in multiferroic BiMnO3 as a function of doping
1International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
Science and Technology of Advanced Materials
|November 24, 2016
Summary
Doping BiMnO3 with various ions reveals its orbitally ordered structure is fragile, often transitioning to an orbitally disordered state. However, the ferromagnetic transition temperature remains stable as long as the ordered phase persists.
Area of Science:
- Materials Science
- Solid State Physics
- Crystallography
Background:
- Bismuth manganite (BiMnO3) exhibits unique multiferroic properties.
- Understanding the structural and magnetic behavior of doped BiMnO3 is crucial for potential applications.
Purpose of the Study:
- To investigate the structural evolution of BiMnO3 upon doping with various isovalent ions.
- To correlate structural changes with magnetic properties and Jahn-Teller distortions.
Main Methods:
- Synchrotron x-ray powder diffraction was employed to analyze the crystal structure.
- Doping was performed on the Bi and Mn sublattices using ions like Cr, Fe, Ga, and La.
- Magnetic measurements were conducted to assess magnetic properties.
Main Results:
- At low doping levels, the orbitally ordered (C2/c(I)) structure of BiMnO3 persists with significant Jahn-Teller distortions.
- Higher doping levels lead to the orbitally disordered (C2/c(II)) structure with reduced distortions.
- Bi0.9La0.1MnO3 showed strong Jahn-Teller distortions, with compressed MnO6 octahedra, adopting the orbitally disordered phase.
- The orbitally ordered state of BiMnO3 is highly sensitive to doping, but its ferromagnetic transition temperature is largely unaffected.
Conclusions:
- Doping BiMnO3 destabilizes its orbitally ordered structure, favoring an orbitally disordered phase.
- Jahn-Teller distortions play a key role in the structural transitions observed.
- Despite structural changes, the ferromagnetic properties remain robust as long as the orbitally ordered phase is maintained.
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