High-Performance Thermomagnetic Gd–Si–Ge Alloys

• Published in: ACS applied materials & interfaces 2023-07, Vol.15 (29), p.35140-35148
• Main Authors: Singh, Saurabh, Liu, Na, Zhang, Yu, Nozariasbmarz, Amin, Karan, Sumanta Kumar, Raman, Lavanya, Goyal, Gagan K., Sharma, Shweta, Li, Wenjie, Priya, Shashank, Poudel, Bed
• Format: Article
• Language: English
• Subjects: Functional Inorganic Materials and Devices
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.3c03158

Exploring low-grade waste heat energy harvesting is crucial to address increasing environmental concerns. Thermomagnetic materials are magnetic phase change materials that enable energy harvesting from low-temperature gradients. To achieve a high thermomagnetic conversion efficiency, there are three main material requirements: (i) magnetic phase transition near room temperature, (ii) substantial change in magnetization with temperature, and (iii) high thermal conductivity. Here, we demonstrate a high-performance Gd5Si2.4Ge1.6 thermomagnetic alloy that meets these three requirements. The magnetic phase transition temperature was successfully shifted to 306 K by introducing Ge doping in Gd5Si4, and a sharper and more symmetric magnetization behavior with saturation magnetization of M max = 70 emu/g at a 2 T magnetic field was achieved in the ferromagnetic state. The addition of SeS2, as a low-temperature sintering aid, to the Gd–Si–Ge alloy improved the material’s density and thermal conductivity by ∼45 and ∼275%, respectively. Our results confirm that the (Gd5Si2.4Ge1.6)0.9(SeS2)0.1 alloy is a suitable composite material for low-grade waste heat recovery in thermomagnetic applications.