Endotaxial alpha-Fe Nanoparticles in the High-Fluence Iron-Implanted Single-Crystal MgO

In this work, we report on the endotaxial growth of alpha-Fe nanoparticles in the near-surface layer under high-fluence iron ion implantation of the single-crystal magnesium oxide substrate. Comprehensive Mossbauer effect and magnetometry studies show that the implanted sample reveals a pronounced ferromagnetic response even at room temperature, and the alpha-Fe nanoparticles serve as its main source. The broad band at similar to 1000 Oe in the X-band magnetic resonance spectra originates from the alpha-Fe fraction. It manifests the properties of the easy-plane system with the four-fold in-plane anisotropy. The last indicates that the alpha-Fe nanoparticles are coherently incorporated into the host MgO matrix.