Band Structure and Thermoelectric Properties of Ni_(x)Zn_(1-x)Fe₂O₄

Abstract:

Thermoelectric materials has made a great potential in sustainable energy industries, which enable the energy conversion from heat to electricity. The band structure and thermoelectric properties of Ni_(x)Zn_(1-x)Fe₂O₄ have been investigated. The bulk pellets were prepared from analytical grade ZnO, NiO and Fe₂O₃ powder using solid-state method. It was possible to obtain high thermoelectric properties of Ni_(x)Zn_(1-x)Fe₂O₄ by controlling the ratios of dopants and the sintering temperature. XRD analysis showed that the fabricated samples have a single phase formation of cubic spinel structure. The thermoelectric properties of Ni_(x)Zn_(1-x)Fe₂O₄ pellets improved with increasing Ni. The electrical conductivity of Ni_(x)Zn_(1-x)Fe₂O₄ pellets decreased with increasing Ni content. The electrical conductivity of Ni_(x)Zn_(1-x)Fe₂O₄ (x = 0.0) is (0.515 x10^-3 Scm^-1). The band structure shows that Zn_xCu_1-xFe₂O₄ is an indirect band gap material with the valence band maximum (VBM) at M and conduction band minimum (CBM) at A. The band gap of Ni_(x)Zn_(1-x)Fe₂O₄ increased with increasing Ni content. The increasing band gap correlated with the lower electrical conductivity. The thermal conductivity of Ni_(x)Zn_(1-x)Fe₂O₄ pellets decreased with increasing Ni content. The presence of Ni served to decrease thermal conductivity by 8 Wm^-1K^-1 over pure samples. The magnitude of the Seebeck coefficient for Ni_(x)Zn_(1-x)Fe₂O₄ pellets increased with increasing amounts of Ni. The figure of merit for Ni_(x)Zn_(1-x)Fe₂O₄ pellets and thin films was improved by increasing Ni due to its high Seebeck coefficient and low thermal conductivity.

• Periodical: Solid State Phenomena (Volume 317)
• Pages: 28-34
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.317.28
• Online since: May 2021
• Authors: Joon Hoong Lim*
• Keywords: Band Structures, Electrical Conductivity, Ni_(x)Zn_(1-x)Fe₂O₄, Seebeck Coefficient, Thermal Conductivity

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