Magnetic and Transport Parameters of LSMO and YBCO/LSMO Films Deposited on Sapphire Substrates

La0.7Sr0.3MnO3 layers and YBa2Cu3O7-δ/La0.7Sr0.3MnO3 bilayers were grown by magnetron sputtering on sapphire substrates. The temperature dependences of the resistance of single La0.7Sr0.3MnO3 films were typical for polycrystalline manganite materials. The resistance decr eases with decreasing of the temperature at medium temperatures and increases at lower and higher temperatures. Deposition of a top YBa2Cu3O7-δ layer led to a drastic increase of the sample resistance. These bilayers did not demonstrate decreasing of the resistance with decrease of the temperature. Temperature dependence of the re- sistance of these samples was interpreted in the framework of a phenomenolog- ical model of two intergrain conduction channels. In framework of this model, parameters of the samples were determined and discussed.