Colossal magnetoresistance properties of La0.83Sr0.17MnO3 thin films grown by MOCVD on Lucalox substrate

The magnetoresistance (MR) of polycrystalline La0.83Sr0.17MnO3 thin films have been studied in high pulsed magnetic fields up to 38 T in the temperature range 100–300 K. The lucalox substrates were used to obtain polycrystalline structures with naturally formed grain boundaries (GBs) and crystallites whose dimensions were determined by film deposition temperature. It was found that the MR value is highest in the films having smallest crystallites. The main behaviour of high-field MR was analysed using modified Mott’s hopping model assuming that the GBs might be ferromagnetic with a Curie temperature T C being reduced in comparison with that of the crystallites interior