Nanocrystalline bulk and thin films of La1−xSrxMnO3 (0≤x≤0.3)

Nanocrystalline La1−xSrxMnO3 has been prepared by a new solution chemistry technique, and the processing parameters were optimized. The thermal history of the as-prepared gel is investigated by differential thermal (DTA) and thermogravimetric analysis (TGA). Formation of La1−xSrxMnO3 starts at temperatures as low as 575 °C. Powder X-ray diffraction analysis was used to check the crystallographic phase purity of nanocrystalline La1−xSrxMnO3. Transmission electron microscopic investigation (TEM) reveals that the grain size of samples prepared at 575 °C were in the range of 20–30 nm. The Mn–K edge EXAFS measurements show the nanocrystalline LaMnO3 and La1−xSrxMnO3 indicate a distortion in the MnO6 octahedra, yielding two discrete Mn–O distance in contrast to structural data obtained for bulk LaMnO3, in which there are three discrete Mn–O distances. Thin films of La1−xSrxMnO3 were deposited by pulsed laser ablation technique on (100) LaAlO3, (1000) sapphire and polycrystalline alumina substrates. The deposition parameters were optimized to realize the growth of high-quality films. Films deposited on (100) LaAlO3 were highly c-axis-oriented while the films on (1000) sapphire were highly a-axis-oriented. The morphology of the films as studied by atomic force microscopic analysis reveal that the films are highly granular with an average grain size in the range of 100–150 nm.