Magnetic, dielectric properties, and scaling behaviors of Aurivillius compounds Bi6-x/3Fe2Ti3-2x(WCo)xO18 (0 ⩽ × ⩽ 0.15).

We investigate the structural, magnetic, dielectric properties, and scaling behaviors of Aurivillius compounds Bi_6-x/3Fe₂Ti_3-2x(WCo)_xO₁₈ (0 ⩽ x ⩽ 0.15). The room-temperature weak ferromagnetism is observed for the W/Co co-doped samples. The results of the dielectric constant ε_r, complex impedance Z", the dc conductivity σ_dc, and hopping frequency f_H manifest that the dielectric relaxation of the x = 0 sample and the doped samples in the dielectric anomaly region (450-750 K) can be ascribed to the trap-controlled ac conduction around the doubly ionized oxygen vacancies and the localized hopping process of oxygen vacancies, respectively. The scaling behaviors reveal that the dynamic process of both electrons in the x = 0 sample and oxygen vacancies in the doped samples is temperature independent. The ferroelectric Curie-temperature T_c decreases slightly from 973K to 947K with increasing the doping level of W/Co. In addition, the dielectric loss exhibits a dielectric relaxation above 800K with the rather large activation energies (1.95 eV ⩽ E_a ⩽ 2.72 eV). [ABSTRACT FROM AUTHOR]