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Understanding Complex Interplay among Different Instabilities in Multiferroic BiMn7O12 Using 57Fe Probe Mössbauer
Iana S Soboleva1, Vladimir I Nitsenko1, Alexey V Sobolev1,2
1Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia.
International Journal of Molecular Sciences
|February 10, 2024
Summary
This study investigates hyperfine interactions in iron-doped bismuth manganite (BiMn7O12) using Mössbauer spectroscopy. It reveals complex structural and magnetic transitions, linking them to dynamic Jahn-Teller effects and proposing a model for spontaneous polarization.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Solid-State Chemistry
Background:
- Quadruple perovskites exhibit complex phase transitions, crucial for their functional properties.
- Understanding hyperfine interactions is key to elucidating magnetic and electrical behaviors in these materials.
- Bismuth manganite (BiMn7O12) is a promising material with potential applications in multiferroics.
Purpose of the Study:
- To investigate the hyperfine electrical and magnetic interactions in 57Fe-doped BiMn7O12.
- To correlate structural and magnetic phase transitions with observed hyperfine parameters.
- To develop a model for spontaneous polarization based on experimental data.
Main Methods:
- Mössbauer spectroscopy was employed to study 57Fe probes in BiMn7O12 over a wide temperature range (10 K to 670 K).
- Analysis of electric field gradient (EFG) parameters and hyperfine interaction parameters.
- Application of the Born effective charge model and effective field approach for polarization analysis.
Main Results:
- A cascade of structural and magnetic phase transitions was observed in BiMn6.9657Fe0.04O12.
- Local dipole moments of Bi3+ ions were confirmed, with random orientation in the paraelectric phase.
- The dynamic Jahn-Teller effect was identified as the cause for unusual hyperfine behavior between structural transitions.
- A model was proposed to describe the spontaneous polarization dependence on temperature, validated by experimental data.
- Complex relaxation behavior was observed in the magnetically ordered states.
Conclusions:
- The study provides detailed insights into the interplay of structural, magnetic, and electrical properties in BiMn7O12.
- The dynamic Jahn-Teller effect significantly influences the material's behavior near phase transitions.
- The proposed model offers a framework for understanding spontaneous polarization in similar perovskite structures.
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