Effect of temperature and AC field duration on the dielectric behavior of PVA/GO/FeGaInS ₄ nanocomposites

This study explores the dielectric behavior of polyvinyl alcohol (PVA)-based nanocomposites incorporating 2 wt% FeGaInS₄ and 3 wt% graphene oxide (GO), focusing on the effects of temperature and alternating current (AC) electric field exposure duration. The nanocomposites were synthesized <i>via</i> ultrasonic dispersion in water, followed by casting and ambient drying. X-ray diffraction (XRD) confirmed the preservation of the FeGaInS₄ crystalline phase and the disordered, exfoliated state of GO within the polymer matrix. Dielectric spectroscopy, performed across 120 Hz to 1 MHz and temperatures between 40 and 80 °C, revealed a decrease in dielectric constant (<i>ε</i>') with frequency, attributed to interfacial and dipolar polarization mechanisms. With increasing temperature, <i>ε</i>' rose due to enhanced chain mobility and interfacial polarization. Notably, 2 h of AC field exposure at 40 °C improved both <i>ε</i>' and dielectric loss (tan <i>δ</i>), while prolonged exposure led to relaxation effects and reduced performance. Activation energy (<i>E</i> _a), calculated using the correlated barrier hopping (CBH) model, decreased from 0.75 to 0.40 eV at 500 Hz with longer field exposure, indicating improved charge hopping. At higher frequencies (50 kHz), <i>E</i> _a showed a transient increase before stabilization. The results demonstrate the tunability of dielectric properties <i>via</i> AC field treatment, highlighting the potential of these nanocomposites for applications in flexible electronics and dielectric energy storage.