Molecular Beam Epitaxy of Ferroic and Multiferroic Thin Films

Epitaxial ferroic oxide thin films and multilayers have been synthesized by oxide molecular beam epitaxy (MBE), for combining materials with different properties such as ferromagnetism and ferroelectricity in a single structure. Fe₃O₄, CoFe₂O₄ and MgFe₂O₄ were deposited, which exhibit sharp interfaces with excellent cube-on-cube orientation. Magneto-optic Kerr effect (MOKE) and SQUID magnetometry measurements indicate that bulk-like magnetic properties can be obtained in the thin films.

Fig. 1A: Cross-section HRTEM of epitaxial CoFe₂O₄ film on SrTiO₃ substrate, showing sharp interfaces with cube-on-cube orientation; Fig. 1B: In-plane MOKE hysteresis loops of Fe₃O₄ and MgFe₂O₄ films.