Role of phonon drag and carrier diffusion in thermoelectric power of polycrystalline La0.97Na0.03MnO3 manganites

Abstract

Abstract:We develop a theoretical model for quantitative analysis of temperature-dependent thermoelectric power of monovalent (Na) doped La 0.97 Na 0.03 MnO 3 manganites. In the ferromagnetic regime, we have evaluated the phonon thermoelectric power by incorporating the scattering of phonons with impurities, grain boundaries, charge carriers and phonons. In doing so, we use the Mott expression to compute the carrier (hole) diffusion thermoelectric power (

Tuning the Phase Separation, Charge Ordering, and Electronic Transport in Electron‐Doped Manganite Films by Piezo‐Strain and Magnetic Field

“…Below T CO , the SR shows an upturn up to 1040% at T = 10 K, implying high sensibility of the CO phase to the strain at low temperatures. This finding signals that a variation of lateral strain by 0.038% gives rise to a maximal relative evolution in the resistance by 1040% for the LHMO film at T = 10 K and H = 0 T. The figure of merit that characterizes the effectiveness of the piezo-strain tunability of resistance β [β = |SR/δε xx |] is 27 368, which is much larger that those for other complex oxide/PMN-PT systems, such as for La 0.9 Ce 0.1 MnO 3 (58), La 0.7 Sr 0.3 MnO 3 (150), La 0.7 Sr 0.3 CoO 3 (7000), NdNiO 3 (40.8), and SrRuO 3 (10). [7,[16][17][18][19] Obviously, the SR is strongly dependent on the magnetic field particularly at low temperatures.…”

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electron-doped) manganites have sparked a surge of research activities as a supplement for the divalent ions substituted (hole-doped) manganites, showing great potential for the development of all-manganites-based p-n junctions and electronic devices. [7][8][9][10] Unlike other tetravalent elements, hafnium has a sole tetravalent or zero valence state. This feature makes La 1-x Hf x MnO 3 an excellent candidate for investigating the electronic structures, Jahn-Teller lattice distortion and double-exchange interaction between the Mn 3+ -Mn 2+ ions in electron-doped manganites instead of that between the Mn 3+ -Mn 4+ ions in hole-doped manganites.

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Defect induced structural and thermoelectric properties of Sb2Te3 alloy

“…36,41,46,47 It has been shown for doped metal di-silicides alloys and skutterudite compounds like In-filled CoSb 3 , the lower lattice thermal conductivity or better thermoelectric performance is likely due to point defect scattering and c-ph scattering, which increases with increasing temperature. 45,47 Also recently, Varshney et al 46 has demonstrated that contribution due to c-ph increases with temperature and improves the thermopower value of polycrystalline manganites at higher temperature. The evidence of enhanced phonon scattering was also experimentally verified on SiGe based thermoelectric materials.…”