Dielectric relaxation analyses

Dielectric spectroscopy is a non-destructive technique for the study of the response of a material subjected to an applied electric field at various frequencies.

• Provides information about the molecular relaxation and dynamics as a function of the electric field.
• Provides the values
• Complex permittivity
• Dielectric losses (tanδ)
• AC conductivity

Device: Novocontrol Alpha Dielectric analyzer for cables and flat specimens

Frequencies: 0.001 Hz up to 10 MHz

Temperatures: -100°C up to +200°C

Voltage: up to 2 kVp

TSDC – Thermally Stimulated Depolarization currents

This is a relaxation technique for investigation of molecular mobility in the solid state with sensitivity comparable to DMA.

Materials: semiconductors, polymers, polymer-clay composites.

Provides information on

• Relaxation mechanisms
• Trap centers and corresponding thermal activation energies
• Trap concentrations.

Operating principle: Thermal detrapping of carriers from defects causes peaks in the leakage current at certain temperatures corresponding to specific trapping centers.

Sensitivity: Densities of electronically active traps as low as 10⁹ cm⁻³ can easily be detected in high resistivity materials.