Formation of antiphase domains in NiFe2O4 thin films deposited on different substrates

Abstract

Thin films of NiFe2O4 have been deposited on various substrates using pulsed laser deposition and the defect structures investigated by transmission electron microscopy. Owing to the simultaneous nucleation of cation-disordered sites during the nonequilibrium growth, the NiFe2O4 films exhibit antiphase domains of ∼20 nm, irrespective of the substrate symmetry. For growth on isostructural spinel substrates, the density of antiphase appears to decrease with decreasing lattice mismatch. Aberration corrected high resolution transmission electron microscopy reveals that the interchange of equivalent tetrahedral cation positions in the host oxygen sublattice as one of the possible mechanisms leading to the formation of antiphase domains.