Dielectric Studies of Ammonium Hydrogen Sulphate (NH₄HSO₄), Embedded into Molecular Sieves SBA-15

Abstract

Temperature dependencies of linear dielectric permittivity and third harmonic coefficient of nanoporous matrices SBA-15 with channel pore size of 7,5 nm filled with ferroelectric NH4HSO4 compared to bulk ammonium hydrogen sulphate were studied. The measurements were performed in a heating and cooling mode with a temperature range from 100 K to room temperature. Low-temperature phase transition shift of 7-8 degrees to low temperatures was found for nanostructured ammonium hydrogen sulphate compared to bulk NH4HSO4. The experimental data were treated within the framework of the models developed for isolated small ferroelectric particles and arrays of coupled particles. The rise of the space charge polarization effects was also observed.