Spin-configurations in thermoelectric MnCoGe materials
Abstract
In the last decades, research for improved thermoelectric materials focused on the introduction of nanostructures. However, only modest enhancement of the thermoelectric efficiency could be achieved. For improved thermoelectric performance another approach is required. In this respect, temperature driven spin transport in magnetic materials offers great potential. The ternary Mn-Co-Ge, for example, shows interesting magnetocaloric and thermoelectric properties. Magnetic properties of ferromagnetic CoxMnyGe1-x-y thin films, for example, have been shown experimentally to vary with composition x and y, suggesting a possible tuning of the CoxMnyGe1-x-y properties to meet application's requirements. In this study, structural and magnetic transitions in MnGe-based materials with varying composition have been investigated using ab initio calculations. In particular, the effect of chemical composition on the stability of the hexagonal Ni2In-type and the orthorhombic TiNiSi-type structure has been examined focusing on their magnetic configurations. It has been found that compressive strain promotes the formation of the Ni2In-type structure which can be advantageous for the magnetostructural transition in thermomagnetic devices. The spin-Seebeck coefficient has been estimated for several magnetic configurations of such materials based on the Boltzmann transport.
This work is financed by the A*MIDEX foundation.- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2017
- Bibcode:
- 2017APS..MARB47005H