Thermoelectric and electrical characteristics of SmS ceramic samples after exposure to a pulsed magnetic field

• Published in: Journal of rare earths 2022-11, Vol.40 (11), p.1778-1784
• Main Authors: Volchkov, Ivan, Baskakov, Evgeniy, Strelov, Vladimir, Kanevskii, Vladimir
• Format: Article
• Language: English
• Subjects: Electric properties; Magnetically induced changes; Rare earths; Samarium monosulfide; Thermoelectric
• ISSN: 1002-0721; 2509-4963
• DOI: 10.1016/j.jre.2022.01.008

Samarium monosulfide (SmS) is a promising material for creating thermoelectric generators (TEG), gas sensors and strain gauges. Despite the high values of the generated thermo electromotive force (TEMF) (α ≈ 170–350 μV/K), methods for increasing the efficiency of TEGs based on SmS are of considerable interest. One of these methods can be short-term effects of magnetic fields, including pulsed ones, on these materials. The action of a pulsed magnetic field (PMF) leading to an increase in TEMF (UT) of SmS ceramic samples is found. Samples that are not subjected to high frequency currents (HFC) annealing show an increase in UT of 44.54%–62.18% (from 11.9 to 17.2–19.3 mV). The conductivity (σ) of the samples is ∼ 22 Ω−1/cm and is insensitive to short-term exposure to a PMF. Samples that undergo HFC annealing show an increase in UT of 23.47%–41.31% (from 21.3 to 26.3–30.1 mV) after exposure to a PMF. The conductivity of the samples is ∼ 15 Ω−1/cm and after a short exposure to the PMF is changing non-monotonically, with an increase in the overall instability. The difference in the values of UT and σ can be explained by presence of an ordered grain structure and a significant amount of the Sm2O2S phase in the samples subjected to HFC annealing. Possible mechanisms of the observed changes are discussed. It is found that the effect of a pulsed magnetic field (PMF) leads to a long-term increase in thermoEMF (UT) of ceramic SmS samples. Samples that were not subjected to annealing by high-frequency currents (HFC) show an increase in UT by 44.54%–62.18% (a) after exposure to PMF. Samples annealed with HFC show an increase in UT of 23.47%–41.31% (b) after exposure to PMF. [Display omitted]