Relaxor ferroelectric phase transition and ac conduction in polycrystalline Gd0.55Ca0.45MnO3 at low temperature

Abstract

The present investigation reports the dielectric phase transition studies in polycrystalline Gd0.55Ca0.45MnO3 along with ac conduction and structural property. Polycrystalline Gd0.55Ca0.45MnO3 has been synthesized by the solid-state synthesis route at 1350 °C which crystallized in the orthorhombic phase with centrosymmetric Pnma symmetry at room temperature. The complex dielectric and modulus properties of polycrystalline Gd0.55Ca0.45MnO3 has been explored in the frequency range of 500 Hz to 1 MHz at low temperatures having the range 6 K–200 K. The real part of dielectric permittivity shows the sharp increase up to 30 K–120 K temperature range and then decreases constantly which confirm the characteristic of relaxor ferroelectric material. The low-temperature dielectric study reveals that Gd0.55Ca0.45MnO3 possesses a high dielectric permittivity and low loss below 120 K. The frequency variation of ac conductivity shows the correlated barrier hopping in the temperature range of 10 K–60 K and 100 K–180 K and gives the signature of small polaron hopping at 60 K–100 K. Thermal variation of activation energy for Gd0.55Ca0.45MnO3 gives the activation energy of 0.0634(2) eV for higher frequency 1 MHz.