  We report the observation of magnetic-field-induced suppression of the spin
Peltier effect (SPE) in a junction of a paramagnetic metal Pt and a
ferrimagnetic insulator ${\rm Y_{3}Fe_{5}O_{12}}$ (YIG) at room temperature.
For driving the SPE, spin currents are generated via the spin Hall effect from
applied charge currents in the Pt layer, and injected into the adjacent thick
YIG film. The resultant temperature modulation is detected by a commonly-used
thermocouple attached to the Pt/YIG junction. The output of the thermocouple
shows sign reversal when the magnetization is reversed and linearly increases
with the applied current, demonstrating the detection of the SPE signal. We
found that the SPE signal decreases with the magnetic field. The observed
suppression rate was found to be comparable to that of the spin Seebeck effect
(SSE), suggesting the dominant and similar contribution of the low-energy
magnons in the SPE as in the SSE.
