  Voltage-controlled spintronic devices utilizing the spin degree of freedom
are desirable for future applications, and may allow energy-efficient
information processing. Pure spin current can be created by thermal excitations
in magnetic systems via the spin Seebeck effect (SSE). However, controlling
such spin currents, only by electrical means, has been a fundamental challenge.
Here, we investigate voltage control of the SSE in the antiferromagnetic
insulator Cr2O3. We demonstrate that the SSE response generated in this
material can be effectively controlled by applying a bias voltage, owing to the
sensitivity of the SSE to the orientation of the magnetic sublattices as well
as the existence of magnetoelectric couplings in Cr2O3. Our experimental
results are explained using a model based on the magnetoelectric effect in
Cr2O3.
