title: Mixed protonic-electronic conduction and dielectric response in layered vanadyl phosphate nanocomposites.
abstract: The layered vanadyl phosphate, VOPO(4)2H(2)O, is employed to prepare nanosized conducting polypyrrole by redox intercalation method. Transport and dielectric properties of various compositions have been investigated by impedance technique over a temperature range of 300-120 K. Grain boundary conductivity is larger than the bulk conductivity. The conductivity reveals a discontinuity at about 212-235 K. The conductivity is predominantly ionic at high temperature and electronic at low temperature. The dielectric spectra reveal a peak in the frequency range up to 2 MHz for higher concentration of intercalated polypyrrole. The activation energy of conductivity relaxation is different from that of total conductivity derived from the impedance plot.
authors.affiliation: Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India.
authors.forename: Sukanta
authors.initials: S
authors.lastname: De
authors.forename: Arup
authors.initials: A
authors.lastname: Dey
authors.forename: S K
authors.initials: SK
authors.lastname: De