Abstract
It has been known that the transition temperature (Tc) of VO2 is shifted by doping specified elements in VO2. In order to shift Tc in still wider range, experiments have been performed with adding various elements. As a result, it has become possible to shift the Tc of VO2 either towards a higher temperature or towards a lower temperature. The doping elements which shift Tc towards a higher temperature are Ti and Ge. Those which shift it towards a lower temperature are Fe, Co, Ni, Mo, Nb, and W. In the research conducted, it has been able to vary the Tc within the range of 0–90°C. As for the relationship between the Tc and the lattice constant of the crystals, there exists a correlation with the cr of the tetragonal phase of VO2. Tc is nearly proportional to the quantity or cr: the more the cr, the higher true Tc is; the less the cr, the lower the Tc is.