Formation of metastable Fe–Cu alloy nanoparticles by ion implantation

• Published in: Thin solid films Vol. 505; no. 1; pp. 152 - 156
• Main Authors: Hayashi, N., Moriwaki, T., Taniwaki, M., Sakamoto, I., Tanoue, A., Toriyama, T., Wakabayashi, H.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 18.05.2006; Elsevier Science
• Subjects: Condensed matter: structure, mechanical and thermal properties; Conversion electron Mössbauer; Cross-disciplinary physics: materials science; rheology; Defects and impurities in crystals; microstructure; Doping and impurity implantation in other materials; Exact sciences and technology; Fe–Cu alloy; Ion implantation; Iron clustering; Materials science; Nanopowders; Nanoscale materials and structures: fabrication and characterization; Physics; Structure of solids and liquids; crystallography; 61.46.yw; 73.43.Qt; Iron clustering; Fe–Cu alloy; Ion implantation; 76.80.ty; 75.50.Bb; Conversion electron Mössbauer; Moessbauer effect; Inorganic compounds; Metastable states; Internal field; Iron alloys; XRD; Nanoparticles; Nanocluster; Magnetization; 73.43.Qt Iron clustering; Experimental study; Magnetic transitions; Precipitates; Binary alloys; Quantity ratio; Copper alloys; Alloying; Magnetoresistance; Nanostructured materials; Fe-Cu alloy; Transition element alloys
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2005.10.028

The formation of the immiscible Fe–Cu nano-clusters by sequential implantations of Fe and Cu ions in crystalline Al 2O 3 is reported in this study. The implantation was performed at room temperature to a total dose of 2.0 × 10 17 ions/cm 2, changing the relative dose of Fe and Cu ions to obtain various Cu concentrations. The possibility of the metastable alloy clusters was investigated by a combined measurement of conversion electron Mössbauer spectroscopy, X-ray diffraction, magneto-resistance (MR) and magnetization. It is shown that the additional Cu implantation leads to both the transitions from super-paramagnetic to ferromagnetic states in the iron nano-clusters aggregated beforehand and also the decrease in the internal fields, suggesting the alloy formation. MR ratio has been found to decrease with increasing Cu dose, indicating also the formation of Cu nano-clusters in the matrices.