Temperature dependent study of the spin Hall magnetoresistance in Pt/ ferromagnetic insulator hybrid structure
Bowen Dong (Institut für Physik)

Recently, heavy non-magnetic metal (HM)/ ferromagnetic insulator (FMI) systems have attracted a lot of attention due to the discovery of a novel spin torque based magnetoresistance effect. In a typical HM/FMI system, like Pt/YIG, a change in the resistance of the nonmagnetic HM layer occurs due to the simultaneously acting of the spin Hall effect and inverse spin Hall effect, which is called spin Hall magnetoresistance (SMR)[1]. The nature of the SMR effect determines its functionality in revealing the spin dependent properties of HM/FMI system. In our experiments we study the temperature dependence of SMR in both Pt/YIG and Pt/GIG systems, which allows us to estimate fundamental material parameter like the spin Hall angle, spin diffuse length of the HM layer and the spin mixing conductance of the interface[2]. In more complex systems, like GIG/Pt, we find a suppression of the SMR near the compensation point of GIG, revealing a correlation between the SMR and the disappearance of the bulk net magnetic moment in GIG[3]. Our study of SMR thereby determines novel behavior of the effect and helps to better understand interface dependent spin current phenomena like the spin Seebeck effect[4].
[1] H. Nakayama, M. Althammer, Y. T. Chen et al., Spin Hall Magnetoresistance Induced by a Nonequilibrium Proximity Effect, Phys. Rev. Lett., 2013, 110(20), 206601.
[2] Y.-T. Chen, S. Takahashi, H. Nakayama et al., Theory of spin Hall magnetoresistance, Phys. Rev. B, 2013, 87(14), 144411.
[3] S. Geprags, A. Kehlberger, F. D. Coletta et al., Origin of the spin Seebeck effect in compensated ferrimagnets, Nat Commun, 2016, 7, 10452.
[4] A. Kehlberger, U. Ritzmann, D. Hinzke et al., Length Scale of the Spin Seebeck Effect, Phys. Rev. Lett., 2015, 115(9), 096602.