IRON EFFECT ON DIELECTRIC PROPERTIES OF CALCIUM-SILICA-PHOSPHATE GLASSES

Dielectric constant εr and loss tan δ of x Fe 2 O 3 · 45(3.34 CaO · P 2 O 5)(55 - x) SiO 2 samples were investigated as a function of composition (0 ≤ x ≤ 30 mol %), temperature and frequency. The samples are characterized by relatively high dielectric constants, which denote bonding defects in the glass network. At all temperatures and frequencies investigated, the dielectric loss for the P 2 O 5- CaO-SiO 2 matrix is lower than that for iron-containing samples. The dielectric constant is higher for the glass matrix than for the iron-containing samples only in the first part of the temperature range. Where the dielectric constant of the glass matrix is higher than the corresponding value for the iron-containing samples the temperature range, exponentially narrows with the decrease of frequency. The dielectric loss in the iron-containing samples is mainly attributed to iron ions conduction.