Crystal structure, magnetism, and thermoelectric properties of Nd.sub.1−x./sub.Sr.sub.x./sub.FeO.sub.3−δ./sub. (0.1 ≤ x ≤ 0.9)

0572183 - ÚJF 2024 RIV GB eng J - Journal Article
Nakatsugawa, H. - Kamatani, Y. - Okamoto, Y. - Hervoches, Charles
Crystal structure, magnetism, and thermoelectric properties of Nd_1−xSr_xFeO_3−δ (0.1 ≤ x ≤ 0.9).
Japanese Journal of Applied Physics. Roč. 62, č. 4 (2023), č. článku 043001. ISSN 0021-4922. E-ISSN 1347-4065
R&D Projects: GA MŠMT EF16_013/0001812
Research Infrastructure: CICRR - 90241
Institutional support: RVO:61389005
Keywords : ZT value * spin state * thermoelectric properties * perovskite type Fe oxides * G-type anti-ferromagnetism with small ferromagnetic order
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 1.5, year: 2022
Method of publishing: Limited access
https://doi.org/10.35848/1347-4065/acc9f3

Polycrystalline Nd1-x Sr x FeO3-delta (0.1 <= x <= 0.9) samples exhibit a single-phase perovskite-type crystal structure and G-type antiferromagnetism with small ferromagnetic order. Assuming that the Fe site is in the mixed-valence state, the spin state of Fe changes from a low-spin (LS) or intermediate spin Fe3+-dominant state at x <= 0.5 to a LS Fe4+ dominant state at x >= 0.6. This strongly suggests that the charge carriers change from holes to electrons. In fact, at temperatures less than 500 K, these samples show a p-type Seebeck coefficient for 0.1 <= x <= 0.5 and an n-type Seebeck coefficient for 0.6 <= x <= 0.9. However, for 0.6 <= x <= 0.9, Fe4+ is reduced to Fe3+ because of an oxygen deficiency in the 500-600 K temperature range. In particular, Nd0.7Sr0.3FeO2.99(1) shows the largest p-type ZT = 0.025 at 765 K, whereas compositions with high n-type ZT could not be identified.
Permanent Link: https://hdl.handle.net/11104/0342955