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Microwave Synthesis and Magnetocaloric Effect in AlFe2B2
Dallas K Mann1, YiXu Wang1,2, Jeanette D Marks1,3
1Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States.
Inorganic Chemistry
|August 14, 2020
Summary
Researchers synthesized AlFe2B2, a magnetic refrigerant, using microwave melting. The Al/Fe ratio significantly impacts its magnetic properties and ordering temperature, crucial for optimizing its performance.
Area of Science:
- Materials Science
- Magnetism
- Solid State Chemistry
Background:
- AlFe2B2 is a promising material for magnetic refrigeration applications.
- Traditional synthesis methods include arc-melting and radiofrequency (RF) induction melting.
- Controlling phase purity and magnetic properties is essential for effective application.
Purpose of the Study:
- To synthesize AlFe2B2 using microwave (MW) melting for the first time.
- To investigate the influence of synthesis method and stoichiometry on AlFe2B2 properties.
- To understand the relationship between Al/Fe ratio, antisite disorder, and magnetic ordering temperature (TC).
Main Methods:
- Synthesis of AlFe2B2 via microwave (MW) melting, arc-melting, and RF induction melting.
- Optimization of synthesis conditions, including excess aluminum and adjusted Fe/B ratios.
- Acid treatment for byproduct removal to achieve phase purity.
- Magnetic property characterization, focusing on ferromagnetic ordering temperatures (TC).
Main Results:
- Successful synthesis of AlFe2B2 using MW melting.
- Phase-pure AlFe2B2 obtained by using excess Al and acid treatment to remove Al13Fe4 byproduct.
- Ferromagnetic ordering temperature (TC) ranges from 280-293 K, influenced by the Al/Fe ratio.
- Decreasing Al/Fe ratio increases TC due to reduced Al/Fe antisite disorder.
- Consistent TC values (286-287 K) and magnetocaloric effect observed across different melting methods with optimized stoichiometry.
Conclusions:
- Microwave melting is a viable method for synthesizing AlFe2B2.
- Stoichiometry, particularly the Al/Fe ratio, is critical for controlling magnetic properties and TC.
- Optimized synthesis conditions lead to consistent and potentially improved magnetic refrigerant performance.
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