  Spin Hall magnetoresistance (SMR) and magnon excitation magnetoresistance
(MMR) that all generate via the spin Hall effect and inverse spin Hall effect
in a nonmagnetic material are always related to each other. However, the
influence of magnon excitation for SMR is often overlooked due to the
negligible MMR. Here, we investigate the SMR in Pt/Y3Fe5O12 (YIG) bilayers from
5 to 300K, in which the YIG are treated after Ar+-ion milling. The SMR in the
treated device is smaller than in the non-treated. According to theoretical
simulation, we attribute this phenomenon to the reduction of the interfacial
spin-mixing conductance at the treated Pt/YIG interface induced by the magnon
suppression. Our experimental results point out that the SMR and the MMR are
inter-connected, and the former could be modulated via magnon excitation. Our
findings provide a new approach for separating and clarifying the underlying
mechanisms.
