Mn4Si7 nanoinclusions in Mn-implanted Si

• Mn4Si7 nanoinclusions are created during high-temperature treatment of silicon implanted with manganese ions.
• The size of Mn4Si7 nanoinclusions increases with annealing temperature while their concentration decreases.
• The presence of magnetic ordering is strongly dependent on the size and concentration of Mn4Si7 nanoinclusions.

Silicon single crystals were implanted with 160 keV Mn+ ions to a dose of 1×1016 cm−2 and next annealed for 1 h up to 1070 K under ambient pressure. Glancing incidence diffraction research performed using synchrotron radiation indicated that the post-implantation treatment influenced the creation of Mn4Si7 nanoinclusions. The dimensions and concentration of these inclusions, calculated from distribution of the X-ray diffuse scattering intensity are dependent on annealing temperature. The sizes and shapes of the inclusions were also determined by high-resolution transmission electron microscopy. Magnetic properties of the Si:Mn samples were studied using superconducting quantum interference device. The origin of ferromagnetic ordering is discussed in terms of the size of nanoinclusions.