Optical spectra of LaMn0.5Ga0.5O3: A contribution to the assignment of the electronic transitions in manganites

We have prepared a LaMn0.5Ga0.5O3 thin film deposited by Pulsed Laser Deposition on a LSAT substrate and we have measured its transmittance in the visible and near UV range, from 300 to 10 K. The aim was to shed light on the origin of the electronic bands in the [MO family through a comparison with the corresponding spectra collected previously on the parent compound. Two our of the four bands detected have been assigned to the intersite d-d transitions between Mn+3 ions. The other ones were ascribed to the p-d Mn-O charge-transfer transitions. We are thus led to a "mixed" interpretation where both a Molt Hubbard and a charge transfer approach concur to interpret the electronic spectrum of those manganites.