Ferromagnetism induced by clustered Co in Co-doped anatase TiO2 thin films

J-Y Kim; J-H Park; B-G Park; H-J Noh; S-J Oh; J S Yang; D-H Kim; S D Bu; T-W Noh; H-J Lin; H-H Hsieh; C T Chen

doi:10.1103/PhysRevLett.90.017401

Ferromagnetism induced by clustered Co in Co-doped anatase TiO2 thin films

Phys Rev Lett. 2003 Jan 10;90(1):017401. doi: 10.1103/PhysRevLett.90.017401. Epub 2003 Jan 10.

Authors

J-Y Kim¹, J-H Park, B-G Park, H-J Noh, S-J Oh, J S Yang, D-H Kim, S D Bu, T-W Noh, H-J Lin, H-H Hsieh, C T Chen

Affiliation

¹ Department of Physics & Electron Spin Science Center, Pohang University of Science and Technology, Pohang, Korea.

PMID: 12570648
DOI: 10.1103/PhysRevLett.90.017401

Abstract

We investigated ferromagnetism of a newly discovered ferromagnetic semiconductor Co-doped anatase TiO2 thin film, using the magnetic circular dichroism (MCD) at the Co L(2,3) absorption edges. The magnetic moment was observed to be approximately 0.1 micro(B)/Co in the measurements, but the MCD spectral line shape is nearly identical to that of Co metal, showing that the ferromagnetism is induced by a small amount of clustered Co. With thermal treatments at approximately 400 degrees C, the MCD signal increases, and the moment reaches up to approximately 1.55 micro(B)/Co, which is approximately 90% of the moment in Co metal. In the latter case, the cluster size was observed to be 20-60 nm.