Synthesis of iron and copper nano-clusters in SiO2 by ion implantation and the magnetic properties

The formation of iron and copper nano-clusters in crystalline SiO2 by sequential implantations of Fe and Cu ions was studied. The implantation was performed at room temperature to a total dose of 1.9×1019 ions/cm2. The addition of Cu ions was done by a dose of 0.7×1017 Cu ions/cm2. It is shown by the measurements of conversion electron Mössbauer spectroscopy and X-ray diffraction that the addition of Cu ions promotes the transitions from superparamagnetic to ferromagnetic states in the iron nano-clusters aggregated beforehand.