Microwave Synthesis and Magnetocaloric Effect in AlFe2B2.

A promising magnetic refrigerant, AlFe2B2, has been prepared for the first time by microwave (MW) melting of a mixture of constituent elements. For comparison, samples of AlFe2B2 have been also prepared by arc-melting, traditionally used for the synthesis of this material, and by induction (RF) melting, which was used in the very first report on the synthesis of AlFe2B2. Although an excess of Al has to be used to suppress the formation of ferromagnetic FeB, the other byproduct, Al13Fe4, is easily removed by acid treatment, affording phase-pure samples of AlFe2B2. Our analysis indicates that the equimolar Fe/B ratio typically used for the preparation of AlFe2B2 might not provide the best synthetic conditions, as it does not account for the full reaction stoichiometry. Furthermore, we find that the initial Al/Fe loading ratio strongly influences magnetic properties of the sample, as judged by the range of ferromagnetic ordering temperatures (TC = 280-293 K) observed in our experiments. The TC value increases with the decrease in the Al/Fe ratio, due to the change in the Al/Fe antisite disorder. The use of the same Al/Fe loading ratio in the arc-, RF-, and MW-melting experiments leads to samples with a more consistent TC of 286-287 K and similar values of the magnetocaloric effect.

[1]  R. Seshadri,et al.  Structural changes upon magnetic ordering in magnetocaloric AlFe2B2 , 2020, Applied Physics Letters.

[2]  M. Sokol,et al.  A progress report on the MAB phases: atomically laminated, ternary transition metal borides , 2019, International Materials Reviews.

[3]  C. M. Hamm,et al.  Microwave heating and spark plasma sintering as non-conventional synthesis methods to access thermoelectric and magnetic materials , 2019, Applied Physics Reviews.

[4]  D. Gregory,et al.  Ultrafast, Energy-Efficient Synthesis of Intermetallics; Microwave-Induced Metal Plasma (MIMP) Synthesis of Mg2Sn , 2019, ACS Sustainable Chemistry & Engineering.

[5]  Vitalij K. Pecharsky,et al.  Designed materials with the giant magnetocaloric effect near room temperature , 2019, Acta Materialia.

[6]  T. Pollock,et al.  Protocols for High Temperature Assisted-Microwave Preparation of Inorganic Compounds , 2019, Chemistry of Materials.

[7]  P. Jia,et al.  Magnetic phase transition and room-temperature magnetocaloric effects in (Al,M)Fe2B2 (M = Si, Ga) compounds , 2019, Journal of Magnetism and Magnetic Materials.

[8]  R. McCallum,et al.  Enhanced room-temperature magnetocaloric effect and tunable magnetic response in Ga-and Ge-substituted AlFe2B2 , 2019, Journal of Alloys and Compounds.

[9]  Tahir Ali,et al.  Phase analysis of AlFe2B2 by synchrotron X-ray diffraction, magnetic and Mössbauer studies , 2017 .

[10]  Stephen D. Wilson,et al.  A Simple Computational Proxy for Screening Magnetocaloric Compounds , 2017 .

[11]  Y. Mozharivskyj,et al.  AlFe2-xCoxB2 (x = 0-0.30): TC Tuning through Co Substitution for a Promising Magnetocaloric Material Realized by Spark Plasma Sintering. , 2016, Inorganic chemistry.

[12]  P. Nordblad,et al.  Magnetic structure of the magnetocaloric compound AlFe2B2 , 2016 .

[13]  L. Häggström,et al.  Mössbauer study of the magnetocaloric compound AlFe2B2 , 2016, 1601.01953.

[14]  L. H. Lewis,et al.  Developing magnetofunctionality: Coupled structural and magnetic phase transition in AlFe2B2 , 2015 .

[15]  Wenyun Yang,et al.  Magnetic frustration and magnetocaloric effect in AlFe2−xMnxB2 (x = 0–0.5) ribbons , 2015 .

[16]  M. Ade,et al.  Ternary Borides Cr2AlB2, Cr3AlB4, and Cr4AlB6: The First Members of the Series (CrB2)nCrAl with n = 1, 2, 3 and a Unifying Concept for Ternary Borides as MAB-Phases. , 2015, Inorganic chemistry.

[17]  S. Stoian,et al.  Investigation of magnetic properties and electronic structure of layered-structure borides AlT{sub 2}B{sub 2} (T=Fe, Mn, Cr) and AlFe{sub 2–x}Mn{sub x}B{sub 2} , 2015 .

[18]  X. Moya,et al.  Caloric materials near ferroic phase transitions. , 2014, Nature materials.

[19]  T. Drysdale,et al.  Modern microwave methods in solid-state inorganic materials chemistry: from fundamentals to manufacturing. , 2014, Chemical reviews.

[20]  M. Shatruk,et al.  Magnetocaloric effect in AlFe2B2: toward magnetic refrigerants from earth-abundant elements. , 2013, Journal of the American Chemical Society.

[21]  V. Franco,et al.  The Magnetocaloric Effect and Magnetic Refrigeration Near Room Temperature: Materials and Models , 2012 .

[22]  J. Lyubina,et al.  Magnetic refrigeration: phase transitions, itinerant magnetism and spin fluctuations , 2012 .

[23]  G. Strouse,et al.  Microwave Synthetic Route for Highly Emissive TOP/TOP-S Passivated CdS Quantum Dots , 2009 .

[24]  G. Strouse,et al.  Microwave synthesis of CdSe and CdTe nanocrystals in nonabsorbing alkanes. , 2008, Journal of the American Chemical Society.

[25]  J. Gerbec,et al.  Microwave-enhanced reaction rates for nanoparticle synthesis. , 2005, Journal of the American Chemical Society.

[26]  P. Weiss,et al.  Le phénomène magnétocalorique , 1917 .