Dielectric study of Al-hydroxy-nontronite

The dielectric behavior of aluminium-hydroxy-nontronite has been studied by the TSDC (thermally stimulated dipolarization current) method as a function of water content, in the 0-20% humidity range. Recorded spectra exhibit three main relaxation regions, corresponding to temperatures of 77-130, 130-200 and 200-300 K respectively, and depending on hydration. The use of special experimental techniques allows the authors to attribute the first region to dipolar reorientation and the second one to the release of charge carriers, most probably of a protonic nature, trapped in the clay structure. The third region seems to be directly related to the quality of the contact of the sample-electrodes configuration