Effects of Defects and Composition on Magneto-Thermoelectric Transport in Mn-Co-Al Family

Mn₂CoAl is one of the first experimentally demonstrated spin-gapless semiconductors (SGSs) [1], with no band gap for one type of electron spin and a finite band gap for the other spin. Mn₂CoAl shows promise for use in spintronic devices, predicted to have high spin-to-charge conversion efficiency at room temperature, which is below the Curie temperature of the compound [1]. Broadly, we plan to establish an accurate mapping of disorder and defects within the single phase region of Mn-Co-Al, using magnetization measurements and chemical composition control to find a reasonable composition working range to achieve SGS behavior. In this talk, we will present results of both temperature- and magnetic field-dependence of magnetization, magnetoresistance, Hall, and Seebeck effect for bulk Mn₂CoAl, synthesized by arc-melting. We will also discuss transport and thermodynamic properties indicative of SGSs and promoting efficient behavior for applications in magneto-electric spin-orbit (MESO) logic devices.

[1] S. Ouardi et al. Phys. Rev. Lett. 110, 100401 (2013).