Structure, transition temperature, and magnetoresistance of titanium-doped lanthanum barium manganite epilayers onto STO 001 substrates

Abstract

We have developed a thin film structure with a maximum magnetoresistance effect (MRE) at room temperature, which is one of the operating requirements for many applications. It is shown that La0.67Ba0.33Ti0.02Mn0.98O3 epilayers obtained by pulsed laser deposition onto (001) SrTiO3 single crystal substrates exhibit the highest MRE, ΔR/R(H)≈150% or ΔR/R(0)≈60% under 5 T, at 300 K, a temperature near to the corresponding Curie temperature (TC). Both doping with a tiny amount of titanium and induced stress due to lattice mismatch between the thin film and the substrate contribute to a decrease in TC as compared to the pristine compound and therefore to the decrease in the temperature where the highest MRE is recorded.