  We demonstrate that an antiferromagnet can be employed for a highly efficient
electrical manipulation of a ferromagnet. In our study we use an electrical
detection technique of the ferromagnetic resonance driven by an in-plane
ac-current in a NiFe/IrMn bilayer. At room temperature, we observe
antidamping-like spin torque acting on the NiFe ferromagnet, generated by the
in-plane current driven through the IrMn antiferromagnet. A large enhancement
of the torque, characterized by an effective spin-Hall angle exceeding most
heavy transition metals, correlates with the presence of the exchange-bias
field at the NiFe/IrMn interface. It highlights that, in addition to strong
spin-orbit coupling, the antiferromagnetic order in IrMn governs the observed
phenomenon.
