Magnetic and thermal induced ordering in V2O5 xerogel films

Abstract In this work we investigated the possibility of using magnetic fields and thermal treatments to induce ordering in V 2 O 5 xerogels in film form. The xerogel was prepared by standard procedures. The films were prepared either by dip-coating or casting. X-ray powder diffraction, cyclic voltammetry as well as conductivity were used to monitor the changes. We found that the freshly made films are unstable, needing at least 48 h of rest at room temperature to have reproducible X-ray diffractograms, as well as conductivities. The changes are attributed to a decrease in film water content. Magnetic field treatments of several hours were observed to increase the ordering of the V 2 O 5 ribbons, as well as the conductivity. For freshly deposited films the effects were larger than those in films left for a few days at room temperature. The electrochemical response of films exposed to magnetic fields did also show an increase in surface homogeneity.