Spin caloric effects in antiferromagnets assisted by an external spin current

TL;DR

This paper predicts novel spin caloric effects in antiferromagnets, including a spin Peltier effect and magnon spin Seebeck effect, enabled by external spin currents and temperature gradients, with potential for magnetic state control.

Contribution

It introduces the concept of spin-current assisted caloric effects in antiferromagnets, including the spin Peltier and spin Seebeck effects, which were not previously described.

Findings

Prediction of spin Peltier effect in antiferromagnetic insulators.

Demonstration that spin current can induce magnon spin Seebeck effect.

The force on domain walls increases with temperature and can surpass direct spin transfer effects.

Abstract

Searching for novel spin caloric effects in antiferromagnets we study the properties of thermally activated magnons in the presence of an external spin current and temperature gradient. We predict the spin Peltier effect -- generation of a heat flux by spin accumulation -- in an antiferromagnetic insulator with cubic or uniaxial magnetic symmetry. This effect is related with spin-current induced splitting of the relaxation times of the magnons with opposite spin direction. We show that the Peltier effect can trigger antiferromagnetic domain wall motion with a force whose value grows with the temperature of a sample. At a temperature, larger than the energy of the low-frequency magnons, this force is much larger than the force caused by direct spin transfer between the spin current and the domain wall. We also demonstrate that the external spin current can induce the magnon spin Seebeck effect. The corresponding Seebeck coefficient is controlled by the current density. These spin-current assisted caloric effects open new ways for the manipulation of the magnetic states in antiferromagnets.