Effect of Cu or Sn Doping on Magnetic Properties of Zn0.98- Fe0.02O Bulk Samples

Polycrystalline bulk samples Zn0.98Fe0.02O doped with Sn or Cu were prepared at 600 oC by a coprecipitation method. The XRD structure analysis shows that all samples are of single phase with the ZnO wurtzite structure. X-ray photoelectron spectroscopy indicates an oxidation state of 4+ for Sn, while a mixed state of 1+ and 2+ for Cu. It is found that Zn0.98Fe0.02O without doping shows weak ferromagnetism at room temperature. Cu doping induces an increase of magnetization at low temperature of 10 K, while Sn doping will seriously suppress the ferromagnetism in the whole temperature range from 300 K to 10 K. This result is consistent with bound magnetic polaron model relative to hole carriers.