Exploration of temperature driven conduction process and ferroelectric properties of Mn doped GdCrO3

Abstract

This work delivers the research findings of the temperature dependent DC resistivity, AC impedance and ferroelectric polarization of GdCr1−xMnxO3 (x = 0 and 0.3). Mixed valence states of Cr (Cr3+ and Cr4+) are explored using the x-ray photoelectron spectroscopy analysis. The exponential decay of DC resistivity on escalating the temperature advocates the semiconducting-like nature for the probed samples. The DC resistivity data of these samples fit well into small-polaron hopping and variable range hopping models. The impedance attributes of these samples were scrutinized over a broad spectrum of temperatures at selected frequencies. The values of the real and imaginary parts of impedance unveil substantial reduction on raising the temperature, thereby signifying the increase in conductivity of the samples. Pristine sample displays an electrical relaxation peak at 65 °C, which translates towards the lower temperature at higher frequencies. Further, the semicircular behavior of Nyquist plots at higher temperatures indicates the reduction of the charge transfer resistance. The equivalent circuits of Nyquist plots are generated using Z-view software. From these plots, it is perceived that grain boundary resistance upsurges while the grain resistance and capacitance drops upon doping. The ferroelectric measurements reveal that the coercive field (Ec) values decrease whereas the values of maximum polarization (Pm), remnant polarization (Pr) and energy storage increase in 30% doped GdCrO3. These observations establish that electrical and ferroelectric properties of GdCrO3 system can be tuned with appropriate Mn doping.