Low-temperature growth of La0.8Sr0.2MnO3 thin films on LaAlO3 and SrTiO3 substrates by an excimer laser metal organic deposition (ELMOD) process

The preparation of La0.8Sr0.2MnO3 (LSMO) films on LaAlO3 (LAO) and SrTiO3 (STO) substrates was examined by an excimer laser MOD processes (ELMOD). Epitaxial LSMO films on the LAO substrate were obtained by the ArF laser irradiation at a fluence of 100 mJ/cm2 for 10, 30, 60 and 90 min with heating at 500 °C. In the case of the STO substrate with heating at 500 °C, epitaxial LSMO was obtained by the ArF laser irradiation at 70 mJ/cm2 whereas no film was formed at 100 mJ/cm2. The effects of the laser fluence, irradiation time and film thickness on the temperature dependence of the resistance and TCR (defined as 1/R·dR/DT) of the LSMO films on the LAO substrate were investigated. It was found that the resistance of the 80 nm thick LSMO film that was irradiated by the ArF laser at a fluence of 100 mJ/cm2 for 60 min showed a metallic temperature dependence from 310 to 100 K, and the maximum temperature coefficient of resistance of the film (TCR: defined as 1/R·dR/DT) was 3.4% at 265 K. In the case of the STO substrate, the resistance of the 80 nm thick LSMO film that was irradiated by the ArF laser at a fluence of 70 mJ/cm2 for 60 min showed a Tc at 280 K, and the maximum TCR of the film was 2.9% at 220 K. The formation mechanisms of the epitaxial LSMO films obtained by the ELMOD process also are discussed.