Reduced magnetocrystalline anisotropy of CoFe${}_2$O${}_4$ thin films studied by angle-dependent x-ray magnetic circular dichroism

Abstract

Spinel-type CoFe${}_2$O${}_4$ is a ferrimagnetic insulator with the Néel temperature exceeding 790 K, and shows a strong cubic magnetocrystalline anisotropy (MCA) in bulk materials. However, when a CoFe${}_2$O${}_4$ film is grown on other materials, its magnetic properties are degraded so that so-called magnetically dead layers are expected to be formed in the interfacial region. We investigate how the magnetic anisotropy of CoFe${}_2$O${}_4$ is modified at the interface of CoFe${}_2$O${}_4$/Al${}_2$O${}_3$ bilayers grown on Si(111) using x-ray magnetic circular dichroism (XMCD). We find that the thinner CoFe${}_2$O${}_4$ films have significantly smaller MCA values than bulk materials. The reduction of MCA is explained by the reduced number of Co${}^{2+}$ ions at the $O_h$ site reported by a previous study [Y. K. Wakabayashi $\text{et al.}$, Phys. Rev. B $\text{96}$, 104410 (2017)].

5 pages, 3 figures

References in corpus (3)

• Electronic structure of normal and inverse spinel ferrites from first principles
• Room temperature spin filtering in epitaxial cobalt-ferrite tunnel barriers
• Anisotropic spin-density distribution and magnetic anisotropy of strained La${}_{1-x}$Sr${}_x$MnO${}_3$ thin films: Angle-dependent x-ray magnetic circular dichroism

Cited by in corpus (2)

• Origin of magnetically dead layers in spinel ferrites $M{\text{Fe}}_2{\text{O}}_4$ grown on ${\text{Al}}_2{\text{O}}_3$: Effects of post-deposition annealing studied by XMCD
• Fe contribution to the magnetic anisotropy of $L{1}_0$-ordered FePt thin films studied by angle-dependent x-ray magnetic circular dichroism