Effects of High Dose Ni, Fe, Co, and Mn Implantation into SnO_2

摘要

The effects of high dose (3 X 10~(16) cm~(-2)) implantation of Ni, Fe, Co, or Mn ions into bulk, single-crystal SnO_2 substrates carried out at substrate temperature of approx 350 deg 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 SnO_2. The Mn-implanted samples remained paramagnetic, as also reported for samples doped during thin film growth, but the Fe, Co-, and Ni-implanted SnO_2 showed evidence of hysteresis with approximate Curie temperatures of approx 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 SnO_2 compared to material doped during pulsed laser deposition suggests the residual implant damage degrades the magnetic properties.