講演情報
[11p-E214-11]Combinatorial Investigation of the Anomalous Nernst Effect in Co2Mn1-xVxAl thin -film
〇(DC)Benugopal Bairagya1,2, Kodchakorn Simalaotao2, Yuya Sakuraba1,2 (1.Uni. of Tsukuba, 2.NIMS)
キーワード：
spintronics、thin film、electronic transport
The anomalous Nernst effect (ANE) offers a promising pathway for transverse thermoelectric energy harvesting and heat flux sensors. While ideal Co2MnAl Heusler alloys maximize topological transport in the L21 phase, thin films often favor a B2 phase. We employed a combinatorial deposition technique to fabricate a continuous composition-spread Co2Mn1-xVxAl film to systematically map properties from Co2MnAl to Co2VAl. Structural analysis revealed the films remain in the B2 phase at low V concentrations, with L21 ordering stabilizing only at x > 0.45. Transverse transport measurements showed diverging trends: while the anomalous Hall conductivity decreased monotonically with V content, the anomalous Nernst coefficient (SANE) exhibited a non-monotonic dependence, maximizing at ~ 1.8 uV/K at x = 0.2. Strikingly, this maximum resides within the B2 region, indicating that the L21 phase is not required for the enhancement of SANE. Instead, the giant ANE is governed by electronic tuning via the Mott relation: V-substitution acts as hole-doping, sweeping the Fermi level (EF) toward the steepest energetic slope of the Berry curvature. Our findings establish that maximizing room-temperature ANE does not require forcing the difficult L21 phase but can be achieved via precise Fermi level engineering within the easily formed B2 phase.