Abstract
We report on the successful fabrication of epitaxial-discrete Co x Fe 3-x O 4 /CoO magnetic nanostructures on a SrTiO 3 substrate as well as the results of a thorough investigation of the magnetic cross-reactions of the two phases in the vicinity of the epitaxial junction. These nanostructures were originally prepared as Fe 3 O 4 -CoO core-shell structures through the phase decomposition of bismuth perovskite precursors by pulsed-laser deposition. An antiphase boundary emerged during the structural/electronic transition from the CoO core to the Co 1-x Fe 2+X O 4 shell; this then developed into a ferrimagnetic/antiferromagnetic interface. Uncompensated spins (UCS) arose from the Co x Fe 3-x O 4 /CoO interface as a result of strong ferrimagnetic-antiferromagnetic interactions. A notable exchange bias as well as a significant exchange enhancement was observed owing to the UCS, which had a locking effect because of the decoupling of the Co 1-x Fe 2+X O 4 /CoO reversal from the antiphase boundary. Control of the precursor ratio allowed for the fine-tuning of the Co 1-x Fe 2+X O 4 phase and the associated locking behaviors. This, in turn, allowed the anisotropy and coercivity of the nanostructures to be manipulated. Thus, we were able to create and thoroughly understand a complex epitaxial configuration with tunable structural and magnetic properties. This study should open new opportunities with regard to current magnetic oxide technology, which requires novel methods for pursuing extremity of controllable properties over an atomic landscape.