Unidirectional spin Hall magnetoresistance as a tool for probing the interface spin polarization of Co2MnSi.
Continuous efforts to develop materials with special electronic properties for spintronics are in progress. For giant magnetoresistance devices, the transport spin polarization at specific interfaces is key and thus requires optimization. We show that measurements of the unidirectional spin Hall magnetoresistance provide a simple approach to access this quantity, which facilitates the process of interface engineering significantly. Based on a Wheatstone-bridge design enabling sensitive dc measurements we probe the unidirectional spin Hall magnetoresistance of Co2MnSi/(Ag, Cu, or Cr)(0.5 nm)/Pt multilayers comprehensively and separate it from thermal contributions. We demonstrate that by the insertion of a thin epitaxial Ag layer the magnetoresistance is doubled corresponding to a significant increase of the transport spin polarization, which is discussed in the framework of highly spin polarized interface states.
Publisher URL: http://arxiv.org/abs/1811.04592