2015/07/28 by Rezwanur Rahman, Rahman, Rezwanur, Douglas K. McCarty +3
Energy · Materials Science · Physics and Astronomy · #Clay minerals and soil interactions #Glass properties and applications #Iron oxide chemistry and applications #cond-mat.soft
paper · pdf · doi:10.48550/arxiv.1507.07973
arXiv admin note: substantial text overlap with arXiv:1502.04101
arxiv created 2015/07/28 · arxiv updated 2015/07/30
We implement a technique to characterize the electromagnetic properties at frequencies 100 to 165 GHz (3 cm-1 to 4.95 cm-1) of oriented smectite samples using an open cavity resonator connected to a sub-millimeter wave VNA (Vector Network Analyzer). We measured dielectric constants perpendicular to the bedding plane on oriented Na+ and Ca++-ion stabilized smectite samples deposited on a glass slide at ambient laboratory conditions (room temperature and room light). The clay layer is much thinner (∼ 30 μm) than the glass substrate (∼ 2.18 mm). The real part of dielectric constant, εre, is essentially constant over this frequency range but is larger in Na+- than in Ca++-ion infused clay. The total electrical conductivity (associated with the imaginary part of dielectric constant, εim) of both samples increases monotonically at lower frequencies (< 110 GHz), but shows rapid increase for Na+ ions in the regime > 110 GHz. The dispersion of the samples display a dependence on the ionic strength in the clay interlayers, i.e., ζ-potential in the Stern layers.