We develop a method to separately investigate the magnetic properties of the nanoparticles and the matrix in granular materials by using x-ray magnetic circular dichroism (XMCD). We reveal that the spin-polarized holes in the nanoparticles penetrate into the matrix and that these holes undergo first order magnetic scattering by the paramagnetic Mn atoms in the matrix, which induces the large MR.

Y. K. Wakabayashi*, et al.
Physical Review B 95, 014417 (2017).