Effect of oxygen partial pressure and Fe doping on growth and properties of metallic and insulating molybdenum oxide thin films

摘要

We report the effect of oxygen partial pressure (OPP) and 5% Fe doping on the structural, electrical, and magnetic properties of MoO_x thin films on c-Al_2O_3 substrate prepared by pulsed laser deposition technique. Detailed analyses of the structural properties suggest that the grown phase of molybdenum oxides and its orientation strongly depend on the OPP as well as Fe doping. Undoped and Fe doped α-MoO_3 films formed at 350 mTorr OPP value show insulating character, where as MoO_2 films formed at lower OPP values reveal metallic behavior. Resistivity minima are observed in Fe doped MoO_2 films, which could be due to weak localization effect or Kondo scattering of the conduction electrons from the Fe impurities. Interestingly, all the Fe doped molybdenum oxide films show magnetic hysteresis at room temperature irrespective of their insulating (MoO_3 phase) or metallic (MoO_2 phase) behavior.