Formation of superconducting regions of MgB2 by implantation of magnesium ions into boron substrate followed by intense pulsed plasma treatment

Mg ion implantation into boron substrates followed by pulsed Ar plasma treatment was used to form MgB2 compound. Rutherford Backscattering (RBS) analysis of the best samples revealed that the ratio of atomic concentration of Mg to B atoms could be close to the stoichiometry of MgB2 in the range of about 100 nm beneath the surface. Results of magnetically modulated microwave absorption (MMMA), magnetic moment and electrical conductivity measurements indicate the presence of superconductive grains with critical temperature T-c=25 K. A gradual onset of microscopic percolation is inferred starting from 15 K although no full percolation has been reached.