Crystallization and related magnetotransport properties of amorphous manganite films grown by metalorganic chemical vapor deposition

La1-xSrxMnO3 films were grown at 450 degreesC by pulsed liquid-injection metalorganic chemical vapor deposition on silicon substrates. The films were amorphous and exhibited a high resistivity (> 10 kOmega cm). Different kinds of annealing (650 degreesC for 1, 3, 6, and 10 h, 800 degreesC for 15 mn, 900 degreesC for 5 mn, and rapid thermal annealings) were performed in order to achieve crystallization through both variations of nucleation and growth rates. X-ray diffraction and transmission electron microscopy were used to characterize the different microstructures obtained. After annealing, the perovskite La1-xSrxMnO3 (xsimilar to0.3) phase was obtained. The resistivity of the films ranged within two orders of magnitude depending on the annealing temperature and time. The magnetoresistive properties were also recovered and similar to those obtained on as-grown polycrystalline films. The rapid thermal annealing process proved to be efficient: the amorphous films exhibited, after a 90 s flash-annealing, an ordering temperature of 340 K, a resistivity of the order of 1 Omega cm, and a low-field magnetoresistance of 20% at 22 K and 0.2 T. (C) 2002 American Institute of Physics.