Effects of high dose Ni, Fe, Co, and Mn implantation into SnO₂

The effects of high dose (3 × 10¹⁶ cm^-2) implantation of Ni, Fe, Co, or Mn ions into bulk, single-crystal SnO ² substrates carried out at substrate temperature of ∼350°C to avoid amorphization of the implanted region on the magnetic properties of the material are reported. X-ray diffraction showed no evidence of secondary phase formation in the SnO₂. The Mn-implanted samples remained paramagnetic, as also reported for samples doped during thin film growth, but the Fe, Co-, and Ni-implanted SnO₂ showed evidence of hysteresis with approximate Curie temperatures of ∼120 K (Co and Cr) or 300 K (Fe). The carrier density in the implanted region appears to be too low to support carrier-mediated origin of the ferromagnetism and formation of bound magnetic polarons may be one explanation for the observed magnetic properties. The much reduced Curie temperature seen in Co-implanted SnO₂ compared to material doped during pulsed laser deposition suggests the residual implant damage degrades the magnetic properties.