Time: 09:30am (UTC/GMT+08:00, Beijing/Shanghai), Apr. 22 (Wedn.), 2020

Online Meeting Room (zoom.com): Click here to join the meeting

Meeting ID: 266 558 076

Speaker: Haiming YU (Beihang University)

Abstract:

The Seebeck effect converts thermal gradients into electricity. As an approach to power technologies in the current Internet-of-Things era, on-chip energy harvesting is highly attractive, and to be effective, demands thin-film materials with large Seebeck coefficients (S). In spintronics, the antiferromagnetic metal IrMn has been used as the pinning layer in magnetic tunnel junctions (MTJs) that form building blocks for magnetic random access memories and magnetic sensors. Spin pumping experiments revealed that IrMn Néel temperature is thicknessdependent and approaches room temperature when the layer is thin. Here, we report that the Seebeck coefficient is maximum at the Néel temperature of IrMn of 0.6 to 4.0 nm in thickness in IrMn-based half MTJs. We obtain a record thermoelectric power S ≈ 390 (±10) uV/K at room temperature. Our results demonstrate that IrMn-based magnetic devices could harvest the heat dissipation for magnetic sensors, thus contributing to the new Power-of-Things paradigm.