Ferromagnetism in a diamond-like carbon film after nickel implantation

Abstract

Mass selective ion beam deposited diamond-like carbon (DLC) films were implanted with Ni+ ions at 30 keV with a fluence of 3.6 × 1016 atoms cm−2. The peak concentration of nickel in the implanted film was calculated to be 12.5% at an implantation depth of ∼30 nm into the DLC film. Raman measurements showed that the integrated intensity of the D peak at ∼1370 cm−1 divided by the G peak at ∼1560 cm−1 increases after ion implantation, which indicates that the implanted films are more graphitic. The implanted film shows ferromagnetic order at room temperature. However the saturation moment of the implanted film increased significantly when the measurement temperature was lowered. This may suggest that implantation leads to a dilute ferromagnetic semiconductor although more research is required.