Epitaxy and magnetotransport of Sr2FeMoO6 thin films

By pulsed-laser deposition epitaxial thin films of Sr2FeMoO6 have been prep ared on (100) SrTiO3 substrates. Already for a deposition temperature of 32 0 degrees C epitaxial growth is achieved. Depending on deposition parameter s the films show metallic or semiconducting behavior. At high (low) deposit ion temperature the FeMo sublattice has a rock-salt (random) structure. The metallic samples have a large negative magnetoresistance which peaks at th e Curie temperature. The magnetic moment was determined to 4 mu(B) per form ula unit (f.u.), in agreement with the expected value for an ideal ferrimag netic arrangement. We found at 300 K an ordinary Hall coefficient of - 6.01 X 10(-10) m(3)/As, corresponding to an electronlike charge-carrier density of 1.3 per FeMo pair. In the semiconducting films the magnetic moment is r educed to 1 mu(B)/f.u. due to disorder in the FeMo sublattice. In low field s an anomalous holelike contribution dominates the Hall voltage, which near ly vanishes at low temperatures for the metallic films only.