Electrical conductivity enhancement of doped-SrO/SrTiO3 Ruddlesden Popper phase prepared by molten salt method

Abstract

SrO/SrTiO3 Ruddlesden Popper (RP) phase is a superlattice oxide compound with alternatively stacking perovskite-type SrTiO3 layers and rock salt SrO layers. This compound is a promising candidate for thermoelectric material with a high electrical conductivity by maintaining the favorable electronic properties and low thermal conductivity. In this present work, we doped the titanium sites with niobium and Sr sites with samarium to improve its electrical properties. The XRD pattern shows the peaks of the sample prepared without addition of salt did not show the formation of a single RP phase powder, on the other hand, the XRD pattern of all doped Sr2Ti1-xNbxO4 and Sr2Ti1-xSmxO4 PR phase samples correspond to that of Sr2TiO4 polycrystalline. Microstructural studies of the particles of the doped and undoped powder were carried out by SEM and showed a similar particle shape and size distribution. The electrical conductivity measurement by LCR meter showed that the substitution in particular site of Sr2TiO4 with higher valence dopants forming Sr2Ti1-xNbxO4 and Sr2Ti1-xSmxO4 increased the number of carrier concentration, thus the electrical conductivity could be improved.