Abstract:
The reflectance of thin films of magnesium doped SrRu03(Mg-SR0) produced by
pulsed laser deposition on SrTiOa (100) substrates has been measured at room temperature
between 100 and 7500 cm~^. The films were chosen to have wide range of
thickness, stoichiometry and electrical properties. As the films were very thin (less
than 300 nm), and some were insulating the reflectance data shows structures due to
both the film and the substrate. Hence, the data was analyzed using Kramers-Kronig
constrained variational fitting (VDF) method to extract the real optical conductivity
of the Mg-SRO films. Although the VDF technique is flexible enough to fit all features
of the reflectance spectra, it seems that VDF could not eliminate the substrate's
contribution from fllm conductivity results. Also the comparison of the two different
programs implementing VDF fltting shows that this technique has a uniqueness
problem.
The optical properties are discussed in light of the measured structural and transport
properties of the fllms which vary with preparation conditions and can be correlated
with differences in stoichiometry. This investigation was aimed at checking the
VDF technique and also getting answer to the question whether Mg^"*" substitutes in
to Ru or Sr site. Analysis of our data suggests that Mg^+ goes to Ru site.
