  We experimentally investigate and quantitatively analyze the spin Hall
magnetoresistance effect in ferromagnetic insulator/platinum and ferromagnetic
insulator/nonferromagnetic metal/platinum hybrid structures. For the
ferromagnetic insulator we use either yttrium iron garnet, nickel ferrite or
magnetite and for the nonferromagnet copper or gold. The spin Hall
magnetoresistance effect is theoretically ascribed to the combined action of
spin Hall and inverse spin Hall effect in the platinum metal top layer. It
therefore should characteristically depend upon the orientation of the
magnetization in the adjacent ferromagnet, and prevail even if an additional,
nonferromagnetic metal layer is inserted between Pt and the ferromagnet. Our
experimental data corroborate these theoretical conjectures. Using the spin
Hall magnetoresistance theory to analyze our data, we extract the spin Hall
angle and the spin diffusion length in platinum. For a spin mixing conductance
of $4\times10^{14}\;\mathrm{\Omega^{-1}m^{-2}}$ we obtain a spin Hall angle of
$0.11\pm0.08$ and a spin diffusion length of $(1.5\pm0.5)\;\mathrm{nm}$ for Pt
in our thin film samples.
