Speaker
Description
Thermoelectric materials are a unique class of materials that enable the conversion of heat (e.g., waste heat) into electric energy, making them crucial for energy harvesting. The most well-known thermoelectric materials are the semiconductors, such as Bi$_2$Te$_3$, widely used for their well-defined thermoelectric properties [1]. However, their preparation is both expensive and time-consuming.
The performance of thermoelectric materials is defined by three physical quantities – the Seebeck coefficient, electrical conductivity, and thermal conductivity. Ideally, the Seebeck coefficient and electrical conductivity should be as high as possible, while thermal conductivity should be minimised. In conventional semiconducting materials, charge carrier diffusion has the most significant impact in determining those properties [2]. However, when the value of the Seebeck coefficient decreases, the value of electrical conductivity increases, creating a challenge in band-engineering of the semiconducting materials, as both values should be maximised.
Recently, new promising materials for thermoelectric applications are being studied – magnetic metals. While charge carrier diffusion remains a fundamental mechanism in all thermoelectric materials, magnetic metals exhibit additional processes – spin fluctuation and the magnon-drag effect – which influence thermoelectric properties without directly affecting charge carriers [2]. This creates an opportunity to enhance thermoelectric performance purely through the material’s magnetic properties.
One such magnetic metal exhibiting thermoelectric properties represents the Heusler alloy Fe$_2$TiAl [3]. Its main benefits include the cost of individual elements and fast preparation via the arc-melting method. This study will focus on optimising the composition of Fe$_2$TiAl to achieve desirable thermoelectric properties at specific temperatures while investigating the contribution of the material’s magnetic behaviour to thermoelectric performance.
Acknowledgements
This work was supported by the projects APVV-16-0079, VEGA-1/0180/23, VEGA-1/0407/24, and University Science Park TECHNICOM for Innovation Applications Supported by Knowledge Technology– II- Phase, ITMS: 313011D232., supported by the Research & Development Operational Programme funded by the ERDF.
References
[1] X. Tang et al., “A comprehensive review on Bi2Te3‐based thin films: Thermoelectrics and beyond,” Interdisciplinary Materials, vol. 1, no. 1. Wiley, pp. 88–115, Jan. 2022. https://doi.org/10.1002/idm2.12009
[2] Z. Gui et al., “Large Improvement of Thermoelectric Performance by Magnetism in Co‐Based Full‐Heusler Alloys,” Advanced Science, vol. 10, no. 28. Wiley, Aug. 04, 2023. https://doi.org/10.1002/advs.202303967
[3] R. O. Suzuki and T. Kyono, “Thermoelectric properties of Fe2TiAl Heusler alloys,” Journal of Alloys and Compounds, vol. 377, no. 1–2. Elsevier BV, pp. 38–42, Sep. 2004. https://doi.org/10.1016/j.jallcom.2004.01.035
