The elevated Curie temperature and half-metallicity in the ferromagnetic semiconductor La${}_x$Eu${}_{1-x}$O

Abstract

Here we study the effect of La doping in EuO thin films using SQUID magnetometry, muon spin rotation ($\mu$SR), polarized neutron reflectivity (PNR), and density functional theory (DFT). The $\mu$SR data shows that the La${}_{0.15}$Eu${}_{0.85}$O is homogeneously magnetically ordered up to its elevated $T_{\mathrm{C}}$. It is concluded that bound magnetic polaron behavior does not explain the increase in $T_{\mathrm{C}}$ and an RKKY-like interaction is consistent with the $\mu$SR data. The estimation of the magnetic moment by DFT simulations concurs with the results obtained by PNR, showing a reduction of the magnetic moment per La${}_x$Eu${}_{1-x}$O for increasing lanthanum doping. This reduction of the magnetic moment is explained by the reduction of the number of Eu-4$f$ electrons present in all the magnetic interactions in EuO films. Finally, we show that an upwards shift of the Fermi energy with La or Gd doping gives rise to half-metallicity for doping levels as high as 3.2 %.

arXiv comment7 pages, 11 figures

References in corpus (7)

• Dilute ferromagnetic semiconductors: Physics and spintronic structures
• Epitaxial influence on the ferromagnetic semiconducotor EuO
• Soft x-ray magnetic circular dichroism study on Gd-doped EuO thin films
• Thickness-dependent magnetic properties of oxygen-deficient EuO
• Effect of Gd doping and O deficiency on the Curie temperature of EuO
• Spatially homogeneous ferromagnetism below the enhanced Curie temperature in EuO_{1-x} thin films
• The phase transition in the localized ferromagnet EuO probed by muSR

Cited by in corpus (3)

• Growth and Characterisation Studies of Eu${}_3$O${}_4$ Thin Films Grown on Si/SiO${}_2$ and Graphene
• Growth of EuO single crystals at reduced temperatures
• Theory of Curie temperature enhancement in electron-doped EuO