Raman effect and unusual transport properties of Co-doped Mn₂FeAl Heusler alloy

¹ Department of Physics, Indian Institute of Technology (Banaras Hindu University) - Varanasi, 221005, India
² Department of Chemistry, Banaras Hindu University - Varanasi, 221005, India
³ School of Material Science and Technology, Indian Institute of Technology (Banaras Hindu University) Varanasi, 221005, India
⁴ Hiroshima Synchrotron Radiation Center, Hiroshima University - 2-313 Kagamiyama, Higashi-Hiroshima 739-0046, Japan

Received: 10 August 2023
Accepted: 28 November 2023

Abstract

Semiconducting materials with a distinctive blend of high electrical and low thermal conductivity are required for efficient thermoelectric devices. In this aspect, Heusler alloys are potential candidates for thermoelectric materials. It has been observed that Co doping in Mn₂FeAl enhances the electrical conductivity as well as reduces the thermal conductivity of the system leading to an improvement in figure of merit. The Seebeck coefficient suggested the p-type behavior over the whole temperature range, followed by a maximum at 150 K. Additionally, the electronic properties of the suggest that the observed Raman mode is due to the electronic excitations in the system. Interestingly, this system shows a decoupling between the Seebeck coefficient and electrical conductivity, suggesting the promising potential of as a thermoelectric material and offering valuable insights into its electronic properties.