Magnetic and optical characterization of ferromagnetic SnO2/Mn multilayers

We have investigated the magnetic and structural properties of Mn/SnO2 multilayers deposited onto Si(1 0 0) substrates at room temperature using the magnetron sputtering method. The nominal Mn layer thickness ranged from 0.4 up to 10 nm. The multilayers structure was studied by X-ray and optical reflectivity. Magnetic measurements indicate the presence of two distinct contributions. One is ferromagnetic with an order temperature above 400 K for all samples and another paramagnetic. Both ferromagnetic and paramagnetic susceptibilities per Mn atom increase as the Mn layer thickness in the multilayers is reduced, corresponding to a more diluted situation. Oscillations in the optical reflectivity measurements are only observed for the sample with nominal Mn layer thickness of 0.4 nm (75 bilayers). In this case, the disappearance of the continuous Mn layers and therefore of the interfaces preserve the necessary transparency. In multilayers with thicker Mn layer, the effective absorption coefficient increases.