Broadband dielectric and conductivity spectroscopy of inhomogeneous and composite conductors

Present facilities in the Department of Dielectrics, Institute of Physics ASCR, enable us to study the complex dielectric/conductivity response of various dielectric, semiconducting and poor-metallic conducting materials and their composites in the frequency range of 10(-5)-10(14) Hz (19 orders of magnitude). Here we summarize the phenomenological models used for fitting and basic understanding of such spectra, particularly of weak inhomogeneous and disordered conductors and composite conductor-dielectric materials within the effective medium approach. For the latter type of materials the electrical percolation phenomena are discussed. The obtained experimental results on several conductor-dielectric composites, particularly around their percolation threshold (PET-CNT, alumina-CNF, PZT-PRO), porous conducting pellets (MoSI, WS2), nanofiber matrix (PVDF-WS2), and variously conducting polyaniline pellets are briefly discussed. (C) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim