Low-temperature growth of La 0.8Sr 0.2MnO 3 thin films on LaAlO 3 and SrTiO 3 substrates by an excimer laser metal organic deposition (ELMOD) process

Abstract

The preparation of La 0.8Sr 0.2MnO 3 (LSMO) films on LaAlO 3 (LAO) and SrTiO 3 (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/cm 2 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/cm 2 whereas no film was formed at 100 mJ/cm 2. 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/cm 2 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/cm 2 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.