Oxygen-dependent transport properties in La_(0.7)Ba_(0.3)MnO_(3-δ) thin films for uncooled infrared bolometric materials

摘要

La_(0.7)Ba_(0.3)MnO_(3-δ)(LBMO) has been noticed as a potential candidate for an uncooled infrared bolometer material, which has a large temperature dependent electrical resistance, as a potential candidate for an uncooled infrared bolometer material. The LBMO thin films were deposited on SrTiO_3 (100) substrates by a laser ablation method. The films were characterized by an x-ray diffractometer. In the observation by an atomic force microscope, the size of the crystal grains and the number of grain boundaries on the films were extremely sensitive on the ambient oxygen pressure during the deposition. The grain size found to have an effect on both the magnitude of the resistivity and the temperature dependence of resistivity. The films deposited under the oxygen pressures of 53.3～80.0Pa, having the temperature dependence of resistivity like a bulk, and it showed a large temperature coefficient of resistance (TCR: defined as 1/R dR/dT) over 3 %K near room temperature.