© 2019 JETIR January 2019, Volume 6, Issue 1 www.jetir.org (ISSN-2349-5162) JETIRDY06235 Journal of Emerging Technologies and Innovative Research (JETIR) www.jetir.org 1482 Review on Thermoelectric properties of Co-based Full-Heusler compounds Navdeep Kaur and Vipul Srivastava * Department of Physics, School of Chemical Engineering and Physical Sciences, Lovely Professional University, Phagwara-144411, Punjab, India Abstract The applications of Heusler compounds in thermoelectric made them valuable for the theoreticians and experimentalists. In this paper thermoelectric properties of Co2MnAl, Co2MnSi and Co2MnGe full-Heusler compounds have been reviewed. The calculations were done by using BoltzTrap code which depends upon the Boltzmann semi-classical transport equation. Seebeck coefficient, electrical conductivity, and thermal conductivity for Co2MnSi and Co2MnAl were calculated by considering both magnetic phases. Co2MnSi was found to be half-metallic in ferromagneic phase and had the highest value for the power factor (2.9×10 -3 Wm -1 k -2 ). Co2MnGe was found to be half-metallic and had the smallest value for figure of merit at room temperature. The calculated values for Seebeck coefficient for Co2MnSi and Co2MnGe were 40×10 -6 VK -1 and 16.7×10 -6 VK -1 respectively. Keywords: Heusler compounds, Thermoelectric properties, Co-based Heusler, BoltzTrap code Introduction The properties like high polarization at fermi level [1], thermoelectric performance [2], ferromagnetism and large Curie temperature [3] made Heusler compounds proficient candidates for spintronics, spin-value generators, magnetoresistive materials, memory devices and thermoelectric materials [4-7]. These eventful compounds were first introduced by Friedrich Heusler in 1903 and their shocking magnetic property of having ferromagnetic behavior without the presence of any magnetic element involve many researchers to investigate them. Cu2MnAl was the first such full-Heusler compound [8, 9] and NiMnSb was the first half-Heusler compound investigated as the half-metallic [10]. There are always three elements in Heusler compounds generally named as X, Y, and Z in which transition elements are taken as X and Y whereas s, p elements are set at the place of Z. The composition of these three elements gives birth to two kinds of Heusler compounds named as half-Heusler (XYZ) and full-Heusler (X2YZ) compounds [11, 12]. The former crystallizes in C1b structure and latter in L21 or XA structure [13], therefore full-Heusler compounds can be investigate by considering two structures. One is L21 also known as Cu2MnAl lie under Fm-3m (225 SG no.) space group and another is XA also known as Hg2CuTi or inverse Heusler compounds lie under F-43m (216 SG no.) space group. In L21 structure (0.25, 0.25, 0.25), (0, 0, 0) and (0.5, 0.5, 0.5) are the atomic positions fixed to X, Y, and Z respectively whilst in XA structure atomic positions (0, 0, 0), (0.25, 0.25, 0.25), (0.5, 0.5, 0.5) and (0.75, 0.75, 0.75) are appointed to X1, X2, Y and Z in the order [14].