Fig. 3: Demonstration of magneto-optical painting of heat current.
a Lock-in thermography method for the AEE measurements. The temperature modulation synchronized with the charge current is extracted by Fourier analysis. b Time charts of the input charge current and output temperature changes induced by the AEE and Joule heating. In the AEE measurements, the square-wave-modulated alternating charge current with the amplitude Jc = 7.0 mA, frequency f = 25.0 Hz, and zero offset was applied to the samples. c Magnetic domain patterns A–F designed via the AO-HDS on the [Co/Pt]4 strips. d Magneto-optical images corresponding to the patterns A–F. e, f Lock-in amplitude A (e) and phase ϕ (f) images for the [Co/Pt]4 strips with the patterns A–F. g ∆T (= Acosϕ) images for the [Co/Pt]4 strips. Each image consists of 192 × 370 pixels. h Surface ∆T profiles along the x direction. The profiles were obtained by averaging 50 x-directional raw profiles along the y direction; the center of the averaged area is marked with black dotted lines in g.