Work

xFe/Bi0.5Sb1.5Te3 thermoelectromagnetic films with coexistence of positive and negative magnetoresistance

Year: 2024

Type: article

Abstract: Thermoelectric (TE) films with excellent electrical transport property are key materials for developing efficient in-plane heat dissipation technology, but their low electrical transport property is a challenge that restricts their application. Recently, a new thermo-electro-magnetic coupling effect has been proposed to significantly improve the comprehensive TE performance. In order to explore the influence of the above effects on the electric transport property of TE films, we develop an integrated preparation method through ball milling dispersion, screen-printing and hot-pressing curing, obtaining a series of xFe/Bi0.5Sb1.5Te3 (BST)/epoxy TE films in which Fe nanoparticles serve as the second phase, resulting in the thermo-electro-magnetic coupling effect , and also we study their influence on the electrothermal transport performance. The results are shown below. The positive and negative magnetoresistance are co-existent in xFe/BST/epoxy thermoelectromagnetic films; the preferred orientation factor of BST (000l) is positively proportional to the positive magnetoresistance (MR+), resulting in an increase of the conductivity; the spin-dependent scattering of negative magnetoresistance (MR–) derived from the local magnetic moment of strong ferromagnetic Fe nanoparticles increases the Seebeck coefficient. Hence, the power factor of Fe/BST/epoxy thermoelectromagnetic film near room temperature reaches 2.87 mW⋅K–2⋅m–1, which is 78% higher than that of BST/epoxy thermoelectric film. These results indicate that the coexistence of positive and negative magnetoresistance in thermoelectromagnetic films can not only relieve the coupling relationship between conductivity and Seebeck coefficient in TE materials, but also provide a new physical mechanism for the excellent TE conversion performance induced by magnetic nanoparticles.

Source: Acta Physica Sinica

DOI: 10.7498/aps.73.20240701