Highly ordered mesoporous magnesium niobate high-κ dielectric ceramic: Synthesis, structural/mechanical characterization and thermal stability

Elisa Tolu, Sebastiano Garroni, Eva Pellicer, Jordi Sort, Chiara Milanese, Piero Cosseddu, Stefano Enzo, Maria Dolors Baró, Gabriele Mulas

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4 Citations (Scopus)

Abstract

The synthesis of a highly ordered mesoporous ternary Mg-Nb oxide by the Evaporation Induced Self-Assembly (EISA) method is presented for the first time. The as-prepared material shows 2D-hexagonal pore periodicity, with unimodal pore size distribution centered at 5.5 nm, and a large surface area (169 m 2 g-1). The mechanical properties, determined by means of nanoindentation, are consistent with the presence of ordered domains of honeycomb-like hexagonal pore arrangements, in agreement with electron microscopy observations and N2 sorption isotherm analyses. The dielectric constant of the mesoporous sample, measured at room temperature in the frequency range 1 kHz to 1 MHz, is rather high (κ ∼ 25 at 1 MHz) and correlates well with the κ value of the bulk and the porosity level of this material. Moreover, the thermal stability of the mesoporous magnesium niobate is investigated after air-annealing treatments at different temperatures. While a significant decrease of the surface area is observed for TANN = 650 °C, the mesostructure fully collapses after annealing at 800°C. © 2013 The Royal Society of Chemistry.
Original languageEnglish
Pages (from-to)4948-4955
JournalJournal of Materials Chemistry C
Volume1
DOIs
Publication statusPublished - 4 Sep 2013

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