Magnetic, dielectric, and magneto-dielectric properties of rare-earth-substituted Aurivillius phase Bi6Fe1.4Co0.6Ti3O18.

We investigate the magnetic, dielectric, and magnetodielectric properties of rare-earth-substituted Aurivillius phase Bi₆Fe_1.4Co_0.6Ti₃O₁₈. The room-temperature ferromagnetic behavior is observed in all samples, and the rare-earth-substituted samples exhibit an enhanced magnetization. The weak ferromagnetism can be ascribed to the spin canting of the antiferromagnetic coupling of the Fe-based and Co-based sublattices via Dzyaloshinsky-Moriya interaction. The dielectric loss of all samples exhibits two dielectric relaxation peaks corresponding to two different relaxation mechanisms. One relaxation process with E_a = 0.5 eV is related to the hoping process of oxygen vacancies and the other one with E_a = 1.6 eV can be ascribed to the intrinsic conduction. The Gd-doped sample exhibits a remarkable magnetodielectric effect (9.4%) at RT implying this Aurivillius phase may be the potential candidate for magnetodielectric applications. [ABSTRACT FROM AUTHOR]