AVS 52nd International Symposium
    Thin Films Monday Sessions
       Session TF-MoP

Paper TF-MoP47
Thermochromic La@sub 1-x@Sr@sub x@MnO@sub 3@ (x = 0.1, 0.175, and 0.3) Smart Coatings Grown by Reactive Pulsed Laser Deposition

Monday, October 31, 2005, 5:00 pm, Room Exhibit Hall C&D

Session: Aspects of Thin Films Poster Session
Presenter: M. Soltani, INRS-Energie, Matériaux et Télécommunications, Canada
Authors: M. Soltani, INRS-Energie, Matériaux et Télécommunications, Canada
M. Chaker, INRS-Energie, Matériaux et Télécommunications, Canada
X.X. Jiang, Canadian Space Agency, Canada
D. Nikanpour, Canadian Space Agency, Canada
J. Margot, Université de Montréal, Canada
Correspondent: Click to Email
Thermochromic Sr-doped LaMnO@sub 3@ thin films exhibit a metallic-to-insulator phase transition from low to high temperature. The transition temperature can be controlled by varying the concentration of Sr@super 2+@ ions dopant in the films. Using a reactive pulsed laser deposition (RPLD) process, we have successfully fabricated thermochromic La@sub 1-x@Sr@sub x@MnO@sub 3@ (LSMO) smart coating at relatively low deposition temperature (about of 500 °C), and without post-annealing. Silicon (100) and sapphire (1000) were used as substrates in order to study the substrate effect on the deposited films. The RPLD of LSMO films was performed in a background gas mixture of Ar and reactive O@sub 2@, from three La@sub 1-x@Sr@sub x@MnO@sub 3@ targets with different Sr doping concentrations (i.e. x = 0.1, 0.175, and 0.3). It was found that the deposited LSMO films perfectly adhere to the wurtzite Al@sub 2@O@sub 3@ as well as to the cubic Si substrate. Their perovskite structure was confirmed by X-ray diffraction (XRD). The composition of LSMO coatings was investigated by X-ray photoelectron spectroscopy (XPS) analysis of the La, Sr, Mn, and O bands. The metal-to-insulator phase transition of LSMO-coated sapphire was investigated by measuring the temperature dependence of the sheet electrical resistivity using the standard four-point probe technique. At room temperature, a thermal coefficient of resistance (TCR) about -1.5 % per °C was achieved in these films. Finally, the potential applications of these thermochromic smart coatings will be discussed.