Strong Spin Hall Effect in the Antiferromagnet PtMn

Effectively manipulating magnetism in ferromagnet (FM) thin film nanostructures with an in-plane current has become feasible since the determination of a 'giant' spin Hall effect (SHE) in certain heavy metal (HM)/FM system. Recently, both theoretical and experimental reports indicate that the non-collinear and collinear metallic antiferromagnet (AF) materials can have both a large anomalous Hall effect (AHE) and a strong SHE. Here we report a systematic study of the SHE in PtMn with several PtMn/FM systems. By using interface engineering to reduce the 'spin memory loss' we obtain a spin torque efficiency as large as 0.24. This is more than twice the previously reported spin torque efficiency for PtMn. We also find that the apparent spin diffusion length in PtMn is surprisingly long (about 2.3nm).