Synthesis and Magnetic Properties of γ-Iron(III) Oxide/Cobalt(II) Oxide and Cobalt(II) Oxide/γ-Iron(III) Oxide Nanostructures for Spintronic Applications

Nguyen Thi Phuong Loan, Hsiao Yi Lee

Abstract

In this study, γ-Fe₂O₃/CoO and CoO/γ-Fe₂O₃ two-component nanoparticles were synthesized using a simple, two-step chemical process. Co(acac)₂ and Fe(acac)₃ were thermally decomposed in hot oleylamine, with mixed nucleation and the subsequent growth of the second component on seed nanoparticles forming the basis of the method. The resulting heterostructures were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and complementary techniques to confirm their composition, structure, and morphology. The nanoparticles exhibited high stability in nonpolar organic solvents due to an in-situ-formed organic coating. Magnetic measurements revealed that the antiferromagnetic CoO phase induces unidirectional anisotropy, arising from both magnetically compensated and uncompensated interfaces. This work demonstrates a facile approach to produce stable, core-shell cobalt-iron oxide nanoparticles with tunable magnetic interactions, suitable for applications in nanomagnetics and spintronic devices.