Figure 4: Spin current by spatial temperature gradient.

(a) Estimation of the electronic temperature gradient of [Co/Pt] in the Cu-200 nm sample from the thermal analysis. (b) Estimation of the spin accumulation at the end of Cu layer of Cu-200 nm sample with the ∇T-driven spin current (red solid line). For comparison, the black solid line is the spin accumulation due to the demagnetization-induced spin current in Fig. 3c. All calculations are done with a pump fluence of 17 J m⁻². (c) Comparison between the spin accumulation data (black circle) and the simulated result (black solid line) of the Cu-200 nm sample with a pump fluence of of 17 J m⁻². The spin accumulation data is taken from Fig. 3b and divided by a factor of two because the data is obtained with a pump fluence of 35 J m⁻². The time delay of the data has been shifted to −0.4 ps for matching with the simulation. The simulation result (black solid line) is the sum of black solid line and red solid line of b.