Epitaxy and magnetotransport of Sr2FeMoO6 thin films

By pulsed-laser deposition epitaxial thin films of Sr2FeMoO6 have been prepared on (100) SrTiO3 substrates. Already for a deposition temperature of 320 degrees C epitaxial growth is achieved. Depending on deposition parameters the films show metallic or semiconducting behavior. At high (low) deposition temperature the FeMo sublattice has a rock-salt (random) structure. The metallic samples have a large negative magnetoresistance which peaks at the Curie temperature. The magnetic moment was determined to 4 mu(B) per formula unit (f.u.), in agreement with the expected value for an ideal ferrimagnetic 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 reduced to 1 mu(B)/f.u. due to disorder in the FeMo sublattice. In low fields an anomalous holelike contribution dominates the Hall voltage, which nearly vanishes at low temperatures for the metallic films only.