Transient response of the spin Peltier effect revealed by lock-in thermoreflectance measurements
Takumi Yamazaki, Ryo Iguchi, Tadakatsu Ohkubo, Hosei Nagano, Ken‐ichi Uchida
Abstract
The transient response and length scale of the spin Peltier effect (SPE) -- heat-current generation due to magnon spin currents -- are revealed by frequency-domain lock-in thermoreflectance. The amplitude of the SPE-induced temperature modulation decreases when the excitation frequency exceeds 1 kHz. The frequency dependence is determined by the characteristic length of the SPE, which is estimated to be 0.94 \textmu{}m for yttrium iron garnet. This length is similar to, but smaller than, the length scale of the spin Seebeck effect, suggesting that the electrically excited magnons in SPE are of a different nature when compared with the thermally excited magnons in the spin Seebeck effect.