Electrochromic WO_(3-x) and Colossal Magnetoresistive (La, Sr)MnO_3 Perovskite Oxide Thin Films by Pulsed Laser Deposition

摘要

The functional oxide thin films of electrochromic WO_(3-x) and colossal magnetoresistive La_(0.8)Sr_(0.2)MnO_3 were prepared by a KrF excimer pulsed laser deposition technique. Optical transparency and electrical conductivity of the WO_(3-x) film were changed by the oxygen content in the lattice. Triclinic, tetragonal and amorphous WO_(3-x) films were prepared by adjusting the oxygen atmosphere during the deposition. We revealed the relationship between the crystal structure and the gas sensing property of the films. The triclinic WO_(3-x) film (1 μm) showed the high sensitivity to NO (60 ppm) gas at an operating temperature of 150℃. The colossal magnetoresistive La_(0.8)Sr_(0.2)MnO_3 thin film having the MR ratio of 15 % (H=7 kG) was deposited under the conditions of the laser energy density of 2 J/cm~2 (5Hz), substrate temperature of 850℃ and oxygen pressure of 500 mTorr. The magnetic sensor composing of the La_(0.8)Sr_(0.2)MnO_3 thin film responded to the AC magnetic field (1 kHz).