Influence of antiphase boundary density on the conduction noise properties of epitaxial magnetite thin films

Low frequency conduction noise (I If noise) properties of epitaxial magnetite (Fe3O4) thin films having a varying density of antiphase boundaries (APBs) were investigated as a function of temperature and frequency. Temperature dependence of noise exhibits a similar behavior to that of resistivity for all the films. The magnitude of normalized noise (S-v/V-2) decreases with the increasing film thickness, which correlates well with the density of APBs. The quantitative feature of noise, i.e., Hooge parameter has a strong thickness dependence at low temperatures which implies that the APBs play an important role in determining the transport mechanism in epitaxial Fe3O4 films. (c) 2005 American Institute of Physics.