High pressure electrical resistivity studies on Ni-doped TiO2 nanoparticles

Electrical resistivity measurement of Ni-doped TiO2 nanoparticles were performed under high pressure using a Bridgman opposed anvil setup. It is observed that, anatase phase nanoparticles shows a sudden increase in resistivity below the pressure limit of 4 GPa and is attributed to the transition from anatase to rutile phase. In addition, the transition limit is shifted towards lower pressure region with increase in dopant concentration. But, Ni-doped TiO2 nanoparticles with rutile phase shows a rapid decrease in resistivity up to 5 GPa and thereafter it becomes constant. Samples with constant resistivity behavior are mainly ascribed to the semiconductor-metallic transformation.

Research highlights
► Understanding of finite size effect on physical properties has been the active area of research in recent years.
► Amongst, high pressure study is one of the important functionality to observe the material's internal structure and/or electronic parameter at nanoscale.
► The high pressure electrical resistivity measurement of Ni-doped TiO2 nanoparticles were done by Bridgman opposed anvil method.
► The electrical parameters are significantly perturbed with two different phases of TiO2 and impurity concentrations. Anatase and rutile phase were obtained by controlling the calcination temperature and are duly confirmed by structural analysis.
► Particle size and morphology of the prepared sample is confirmed by SEM and HRTEM analysis.