Multiferroic property, dielectric response, and scaling behavior in Aurivillius Bi4.25Gd0.75Fe0.5Co0.5Ti3O15 ceramic

Abstract

We investigate the structural, magnetic, ferroelectric properties, dielectric response, and scaling behavior of Aurivillius compound Bi4.25Gd0.75Fe0.5Co0.5Ti3O15. The substitution of Gd can effectively enhance the room-temperature ferromagnetic property. The ferromagnetic and ferroelectric Curie temperature can be determined to 370 K and 1088 K, respectively. Four thermally activated dielectric relaxations in the temperature range of 10–1000 K are observed. The first dielectric relaxation in cryogenic temperature range (50–100 K) can be attributed to electron hopping between Co2+ and Co3+ through bridging oxygen vacancies Vo. The second one in 300–500 K can be ascribed to the electron localized transfer between Co2+ and Co3+. The third one in dielectric anomaly region (500–800 K) arising from the trap-controlled ac conduction around the doubly ionized oxygen vacancies Vo. The last one in high temperature range (above ∼800 K) may be originate from viscous motion of domain wall. Moreover, scaling behavior reveals the dynamic process of electrons is independence of temperature.