Quasi-intrinsic colossal permittivity in Nb and In co-doped rutile TiO2 nanoceramics synthesized through a oxalate chemical-solution route combined with spark plasma sintering

Hyuksu Han (1) , Pascal Dufour (1) , Sungwook Mhin (2) , Jeong Ho Ryu (3) , Christophe Tenailleau (1) , Sophie Guillemet (1)

1 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
2 Korea Institute of Industrial Technology
3 KNUT - Korea National University of Transportation

Nb and In co-doped rutile TiO2 nanoceramics (n-NITO) were successfully synthesized through a chemical-solution route combined with a low temperature spark plasma sintering (SPS) technique. The particle morphology and the microstructure of n-NITO compounds were nanometric in size. Various techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric (TG)/differential thermal analysis (DTA), Fourier transform infrared (FTIR), and Raman spectroscopy were used for the structural and compositional characterization of the synthesized compound. The results indicated that the as-synthesized n-NITO oxalate as well as sintered ceramic have a co-doped single phase of titanyl oxalate and rutile TiO2, respectively. Broadband impedance spectroscopy revealed that novel colossal permittivity (CP) was achieved in n-NITO ceramics exhibiting excellent temperaturefrequency stable CP (up to 104) as well as low dielectric loss (B5%). Most importantly, detailed impedance data analyses of n-NITO compared to microcrystalline NITO (m-NITO) demonstrated that the origin of CP in NITO bulk nanoceramics might be related with the pinned electrons in defect clusters and not to extrinsic interfacial effects.

Mots clés: TiO2 nanoceramics

Domaines: Matériaux

Hyuksu Han, Pascal Dufour, Sungwook Mhin, Jeong Ho Ryu, Christophe Tenailleau, et al.. Quasi-intrinsic colossal permittivity in Nb and In co-doped rutile TiO2 nanoceramics synthesized through a oxalate chemical-solution route combined with spark plasma sintering. Physical Chemistry Chemical Physics, 2015, 17 (26), pp.16864-16875. ⟨10.1039/c5cp02653a⟩. ⟨hal-02003098⟩