(V,Nb):TiO2 - a transparent conductor and ferromagnetic semiconductor !?

Both the property combinations a) transparent conductivity and b) diluted magnetic semiconductivity are based on the concept of dispersed substitutional doping of a suitable semiconductor with dopants that provide free electrons and/or carry a magnetic moment. The implications of current point defect theory with respect to defect formation enthalpies in anatase TiO2 are discussed in context with experimental results on electrical, optical and magnetic properties of V and Nb doped TiO2 thin films prepared by reactive magnetron sputtering. While transparent conductivity could be achieved via Nb doping, V doped films remain paramagnetic (in contrast to theoretical predictions).