Tuning transport and magnetic properties of CoxFe3-xO4 thin films by Co content

We systematically investigated the influence of the Co content on the magnetic and transport properties of spinel CoxFe3-xO4 (0 <= x <= 1) thin films on MgO (001) substrates prepared by molecular beam epitaxy. Our films exhibited the spinel structure as expected. The Verwey transition was clearly observed in Fe3O4 and Co0.6Fe2.4O4, while it disappeared with higher Co contents. Electrical resistivity increased with the Co content from 0.003 Omega-cm for x = 0 to 1.5 Omega-cm for x = 1 at 300 K. As expected, magnetization curves show an increase of the coercive fields of the samples with the Co content. In addition, the samples reveal complex magnetic properties that are explained by a reorientation of the anisotropy easy axis from the crystal < 111 > directions to the < 100 > directions with the Co content. (C) 2018 Elsevier B.V. All rights reserved.