Effect of Temperature, Pressure and Aging time on the Relaxation Dynamics of Bi0.9Gd0.1Fe0.9Mn0.1O3 System: Direct Evidence of Glassy State and Pressure Induced Relaxor Behavior

TL;DR

This study investigates how temperature, pressure, and aging influence the relaxation dynamics of Bi0.9Gd0.1Fe0.9Mn0.1O3, revealing glassy states and pressure-induced relaxor behavior with implications for understanding multiferroic materials.

Contribution

It provides new experimental evidence linking high pressure to relaxor behavior and elucidates the relaxation mechanisms in a complex multiferroic system.

Findings

Identification of three relaxation processes across a wide frequency range

Evidence of glassy state below 200 K from aging experiments

Pressure induces a transition from ferroelectric to relaxor behavior

Abstract

The fundamental aspects of relaxation dynamics in Bi0.9Gd0.1Fe0.9Mn0.1O3 multiferroic system have been reported. The study was carried out employing dielectric relaxation spectroscopy covering eight decades in frequency 0.01 to106 Hz and in a wide range of temperature 423 K to 153 K, hydrostatic pressure 0.1 MPa to 1765 MPa and aging time 0 s to 80000 s. The temperature dependent dielectric response indicates three relaxations processes in the dynamic window of modulus formalism. Variable range hopping model of small polarons manifests the bulk conduction mechanism. The bulk and grain boundary contributions have been estimated using impedance spectroscopy analysis and reveal that localized process dominates the relaxation. The direct evidence of glassy feature is established below 200 K by aging experiments. Our findings provide a potential connection between nearly constant loss features appearing below 200 K with fastest relaxation of magnitude 0.16 eV. We also discuss the time temperature superposition behavior using modulus scaling. A pressure driven normal ferroelectric to relaxor behavior is witnessed above a critical pressure as a result of relative competition between short range and long range forces. Our findings focus the role of high pressure as a fundamental bridge between normal ferroelectrics and relaxors. Intriguingly, there exists a direct connection between chemical pressure induced by substitution and external hydrostatic pressure. These findings have robust fundamental importance on theoretical elucidation of relaxation dynamics in perovskite systems.