Magneto-optical studies in NiO/Fe2O3 multilayers

[Fe2O3/NiO](N) multilayer films prepared by pulsed laser deposition display oscillation observed in the magnetization M as a function of N or the numb er of interfaces i = 2N - 1 indicating that they are not symmetric. In this work magneto-optic (MO) polar Kerr rotation spectra of some samples in the photon energy range 1.2-4.5 eV are reported. Faraday rotation (FR) was stu died at 632.6 and 550 nm laser wavelengths. It shows the oscillations with N in accordance with M. Polar Kerr rotation spectra show a series of peaks which could be assigned to nickel ferrite NiFe2O4 formed at the interfaces between NiO and alpha Fe2O3. The amplitudes change strongly with N as expec ted from N dependence of FR and M. A simple analytical expression is propos ed to explain the complex phase relations among the contributions from indi vidual ferrimagnetic interfaces to the total MO Kerr rotation in the multil ayers. (C) 1999 American Institute of Physics. [S0021-8979(99)46608-3].