Transport and magnetic properties of Bi2Fe4O9–Fe3O4 nanocomposite films grown on LaAlO3 (100) substrates by molecular beam epitaxy

Abstract The growth of 79% Bi2Fe4O9−21% Fe3O4 nanocomposite films on (100) LaAlO3 substrates using molecular beam epitaxy is reported. X-ray diffraction and field emission scanning electron microscopy confirmed that the nanocomposites consisted of an orthorhombic phase of lamellae Bi2Fe4O9 embedded in a face-centered-cubic (fcc) phase of a nanorod-like Fe3O4 matrix. Consequently, nanocomposite films exhibit a significant change of the Verwey transition temperature (TV) as the tailoring heteroepitaxial constraints along the vertical interfaces between the Fe3O4 and Bi2Fe4O9. A possible explanation for the peak at 260 K, referred to as the Neel temperature (TN), is that the magnetization curve is superimposed ferromagnetic Fe3O4 with antiferromagnetic Bi2Fe4O9 components.