Polyol synthesis of (polyvinylpyrrolidone) PVP-Mn3O4 nanocomposite

We report on the synthesis of (polyvinylpyrrolidone) PVP-Mn3O4 nanocomposite via a polyol route. Crystalline phase was identified as Mn3O4 and the crystallite size was obtained as 6 ± 1 nm from X-ray line profile fitting. Average particle size of 6.1 ± 0.1 nm obtained from TEM analysis reveals nearly single crystalline nature of these nanoparticles in the composite. The capping of PVP around Mn3O4 nanoparticles was confirmed by FT-IR spectroscopy, the interaction being via bridging oxygens of the carbonyl (C=O) and the nanoparticle surface. TC and TB for PVP-Mn3O4 nanocomposite were observed at 42 K and 28.5 K, respectively. The sample has hysteresis with small coercivity and remanent magnetization at 40 K, resembling the superparamagnetic state. ac conductivity measurements on PVP-Mn3O4 nanocomposite revealed a conductivity in the order of 10-7 S cm-1 at lower frequencies. The conductivity change with respect to frequency can be explained by electronic exchange occurring between Mn+2 and Mn+3 existing in sublattice of spinel lattice.