Thermoelectric Transport Properties and Mg Doping Effect of CuCr1-xMgxO2Polycrystals with c-Axis Orientation
CUI Kai1, YU Lan1, LIU Anan1, QIN Meng1,2, SONG Shijin1, SHEN Yan1
1 Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093 2 Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai 200050
Abstract: CuCr1-xMgxO2(0≤x≤0.08) polycrystalline samples with c-axis orientation were prepared by solid-state reaction. The microstructure and thermoelectric transport properties of the samples were characterized by X-ray diffraction, scanning electron microscopy, resistivity-temperature and Seebeck coefficient-temperature curves. In the single-phase delafossite structure with increasing Mg doping amount within x=0—0.03, the crystal grains grow significantly along the ab-plane and (00l) lotgering factor is up to 0.53, the grain boundary and pore decrease significantly, and the density increases successively. The polycrystalline samples exhibit semiconducting electrical transport behavior according with Arrhenius thermal activation mode. The activation energy decreases from 0.273 eV to 0.031 eV, and the conductivity increases by 3—4 orders of magnitude at room temperature, the Seebeck coefficient at high temperature decreases from 481.2 μV·K-1to 334.7 μV·K-1and increases with the increasing temperature which due to the contribution of phonon drag in the Mg-doped samples. After x>0.03, the thermoelectric transport remain basically unchanged, the polycrystalline microstructure changes little, and the MgCr2O4 octahedral spinel phase is observed at the grain boundary. In conclusion, the maximum solid solubility of Mg doping is 0.03. As Mg2+ replace the Cr3+ sites, they introduce an acceptor level and expanding near the top of the valence band, causing the thermal activation energy of the electrical transport drops significantly. The increased hole carrier concentration and the stronger c-axis orientation with more transport component in ab-plane are mainly account for the conductivity enhancement. The effect of carrier mobility is secondary.
Fang Z J, Zhu J Z, Zhou J, et al. Chinese Physics B, 2012, 21(8), 1.2 Poienar M, Hardy V, Kundys B, et al. Journal of Solid State Chemistry, 2012, 185(5), 56.3 Huang H, Zhu C F, Liu W. Chinese Journal of Chemical Physics, 2004, 17(2), 162.4 Dong G B, Zhang M, Lan W, et al. The Chinese Journal of Nonferrous Metals, 2007, 17(9), 1471.5 Lee M S, Kim T Y, Kim D. Applied Physics Letters, 2001, 79(13), 2028.6 Zheng S Y, Jiang G S, Su J R, et al. Materials Letters, 2006, 60, 3871.7 Yasuhiro O, Kenichi S, Tomohiro N, et al. In: International Conference on Thermoelectrics. Japan, 2007, pp. 1071.8 Nagarajan R, Draeseke A D, Sleight A W, et al. Journal of Applied Physics, 2001, 89(12), 8022.9 Li Y C, Zhang M, Dong G B, et al. The Chinese Journal of Nonferrous Metals, 2010, 20(5), 898 (in Chinese).李杨超, 张铭, 董国波, 等.中国有色金属学报, 2010, 20(5), 898.10 Song X Y, Yang Y Z, Liu Y, et al. Electronic Components and Mate-rials, 2013, 32(8), 38 (in Chinese).宋晓英, 杨元政, 刘远, 等.电子元件与材料, 2013, 32(8), 38.11 Zhao F, Liu Y J, Li N, et al. Journal of Molecular Catalysis, 2001, 15(3), 161 (in Chinese).赵峰, 刘英骏, 李能, 等.分子催化, 2001, 15(3), 161.12 Maignan A, Martin C, Frésard R, et al. Solid State Communications, 2009, 149, 962.13 Guilmeau E, Poienar M, Kremer S, et al. Solid State Communications, 2011, 151, 1798.14 Morimura T, Yamaguchi T, Kojima T, et al. Journal of Electronic Mate-rials, 2014, 43(6), 1603.15 Song S J, Ni J, Yu L, et al. Journal of the Chinese Ceramic Society, 2015, 43(3), 286 (in Chinese).宋世金, 倪佳, 虞澜, 等.硅酸盐学报, 2015, 43(3), 286.16 Okuda T, Jufuku N, Hidaka S, et al. Physical Review B, 2005, 72(14), 1.17 Kurtz S K, Carpay F M A. Journal of Applied Physics, 1980, 51(11), 5725.18 Senda T, Bradf R. Journal of the American Chemical Society, 1990, 73(1), 106.19 Fan K. Preparation, photoelectric properties and LIV effect of CuCr1-x-MgxO2 with wide bandgap. Master’s Thesis, Kunming University of Science and Technology, China, 2016 (in Chinese).樊堃. 宽禁带CuCr1-xMgxO2材料的制备及光、电性能和LIV效应研究. 硕士学位论文, 昆明理工大学, 2016.20 Wang Y, Yu L, Wang J H, et al. Materials Letters, 2012, 75(3), 39.21 Feng X L, Xie L Y, Su J R. Materials Review, 2011, 25(S2), 338 (in Chinese).冯晓莉, 解林燕, 苏金瑞.材料导报, 2011, 25(专辑18), 338.22 Macdonald D K C. Thermoelectricity: An introduction to the principles, Wiley, America, 1962.23 Arnold T, Payne D J, Bourlange A, et al. Physical Review B, 2009, 79(7), 45.
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2019, Vol. 33 
