Fig. 2: Temperature-dependent Seebeck effect measured on a meandering thermopile.
From: Record thermopower found in an IrMn-based spintronic stack
a An illustrative diagram of the thermopile consisting of periodic IrMn-based thin film bars connected in series with gold leads. The temperature difference ∆T is applied in-plane by a Joule heater (Supplementary Note 6 and Supplementary Fig. 5). The inset shows a high angle annular dark field scanning transmission electron microscopy (HAADF STEM) image of the IrMn-based magnetic multilayer, where tAFM is the IrMn layer thickness. The black scale bar is 5 nm. b A color-coded scanning electron microscope (SEM) image of the meandering thermopile. The green and yellow bars are the 800 nm wide IrMn-based thin films and the 400 nm wide gold leads. The white scale bar is 2 µm. c The Seebeck voltage measured on the sample with IrMn thickness tAFM = 2.8 nm, from 10 to 350 K. The antiferromagnetic (AFM) phase in light blue and paramagnetic (PM) phase in white are divided by a critical temperature Tcrit ≈ 285 K. The dashed line indicates room temperature. Inset shows the Seebeck voltage measured at RT as a function of the heating current up to 5 mA. Red squares are measured data. The black line shows a quadratic fit to the data.
