Combinatorial fabrication and characterization of ternary la ₂O₃-Mn₂O₃-Co₃O ₄ composition spreads

We describe the screening of large combinatorial oxide libraries for determining their electric transport characteristics. Complete full ternary composition spreads of La₂O₃-Mn₂O ₃-Co₃O₄ oxide alloys were deposited onto single conducting Nb-doped SrTiO₃ substrates by the pulsed laser deposition technique incorporating a moving shutter and a rotating substrate holder. The electrical resistance of the spreads was determined using a custom-designed scanning conducting probe. We found that a single electrically conducting area in the ternary spread develops into two branches to LaMnO₃ perovskites close to the ideal LaMnO₃ stoichiometry and to a wide La_0.65Co_0.35O_x-La_0.20Co _0.80O_x system with perovskite-related structures. We also discovered that compositions along the tie line [La_0.20Co _0.65Mn_0.15O_X-La_0.57Co _0.20Mn_0.23O_X] exhibit the weakest temperature dependence and therefore could be used in fabricating of stable thin film resistors and gas sensors.