Effects of substrate temperature and oxygen pressure on the magnetic properties and structures of CoFe2O4 thin films prepared by pulsed-laser deposition

CoFe2O4 thin films were grown on silicon substrates by pulsed-laser deposition techniques at various temperatures from 350 degrees C to 700 degrees C and different pressures from 0.1 Pa to 10 Pa. The CoFe2O4 films with highly (1 1 1)-preferred orientation and smooth surfaces were obtained. The high coercivities of the films were attributed to the residual stress in the films, and the saturation magnetizations were mainly dependent on the oxygen pressure. Higher oxygen pressure could decrease the oxygen deficiencies in the films. Sufficient oxygen ions in the films enhanced the exchange interactions between the magnetic ions, as a result, increasing the saturation magnetization. (c) 2007 Elsevier B.V. All rights reserved.