Magnetic orientation of Ni in Zn-Ni ferrites studied by soft-x-ray magnetic circular dichroism

We report the Ni ${\mathrm{L}}_{2,3}$-edge magnetic circular dichroism (MCD) measurements of ferrimagnetic ${\mathrm{Zn}}_{\mathrm{x}}$ ${\mathrm{Ni}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Fe}}_2$ ${\mathrm{O}}_4$ (x=0.0, 0.26, 0.50, and 0.75). The Ni MCD asymmetry ratio was found to decrease with increasing x, showing a reduction of the Ni average magnetic moment with Zn content. This observation is interpreted in terms of the variations in the Yafet-Kittel-type canted angles of the Ni moment, giving new insight into the superexchange interactions involving the Ni ions. A comparison with the non-Ni-specific neutron scattering and Mössbauer studies is given.