Zhensong Ren

n-type thermoelectric material Mg2Sn0.75Ge0.25 for high power generation

Significance Thermoelectric materials have been extensively studied for applications in conversion of waste heat into electricity. The efficiency is related to the figure-of-merit, ZT = (S2σ/κ)T, where S, σ, and κ are the Seebeck coefficient, electrical conductivity, and thermal conductivity, respectively. Pursuing higher ZT for higher efficiency has been the focus by mainly reducing the thermal conductivity. In this paper, we point out, for a given ZT, higher power factor (S2σ) should be pursued for achieving more power because power is determined by (Th − Tc)2(S2σ)/L, where Th, Tc, and L are the hot and cold side temperatures, and leg length, respectively. We found a new material, Mg2Sn0.75Ge0.25, having both high ZT and high power factor. Thermoelectric power generation is one of the most promising techniques to use the huge amount of waste heat and solar energy. Traditionally, high thermoelectric figure-of-merit, ZT, has been the only parameter pursued for high conversion efficiency. Here, we emphasize that a high power factor (PF) is equivalently important for high power generation, in addition to high efficiency. A new n-type Mg2Sn-based material, Mg2Sn0.75Ge0.25, is a good example to meet the dual requirements in efficiency and output power. It was found that Mg2Sn0.75Ge0.25 has an average ZT of 0.9 and PF of 52 μW⋅cm−1⋅K−2 over the temperature range of 25–450 °C, a peak ZT of 1.4 at 450 °C, and peak PF of 55 μW⋅cm−1⋅K−2 at 350 °C. By using the energy balance of one-dimensional heat flow equation, leg efficiency and output power were calculated with Th = 400 °C and Tc = 50 °C to be of 10.5% and 6.6 W⋅cm−2 under a temperature gradient of 150 °C⋅mm−1, respectively.

Synthesis and characterization of La0.825Sr0.175MnO3 nanowires

Perovskite oxide La0.825Sr0.175MnO3 (LSMO) nanowires are synthesized using the anodized alumina oxide template technique and the characterization of the microstructure, magnetic and photoluminescence properties is performed. The as-prepared LSMO nanowires 50 nm in diameter and tens of microns in length exhibit polycrystalline perovskite structure. The magnetic measurement reveals the competition between antiferromagnetic ordering and spin glass state as ground state in the nanowires, which is different from the magnetic behaviours of bulk ceramic and single crystals. The photoluminescence (PL) spectroscopy demonstrates strong and broadband emissions with two luminescent peaks at 400 and 420 nm, respectively, which are believed to originate from the self-trapped excitons, oxygen vacancies and surface states, respectively.

Neutron scattering study of correlated phase behavior in Sr 2 IrO 4

Neutron diffraction measurements are presented exploring the magnetic and structural phase behaviors of the candidate J

Neutron scattering study of magnetic phase separation in nanocrystalline La5/8Ca3/8MnO3

_{eff}=1/2

Carrier localization and electronic phase separation in a doped spin-orbit-driven Mott phase in Sr 3 (Ir 1– x Ru x ) 2 O 7

Mott insulating iridate Sr

Anomalous vibrational properties of cubic boron arsenide

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Low temperature thermoelectric properties of p-type copper selenide with Ni, Te and Zn dopants

IrO

Switchable Plasmonic–Dielectric Resonators with Metal–Insulator Transitions

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Thermoelectric properties of CeAl3 prepared by hot-press method

. Comparisons are drawn between the correlated magnetism in this single layer system and its bilayer analog Sr

Enhanced Thermoelectric Performance of Te-doped FeSb_{2} Nanocomposite

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