Doping stimulated ferromagnetic ordering and tailoring of the dielectric properties of Ba1−xCexTiO3

Abstract

The concurrent integration of ferroelectricity and ferromagnetism in BaTiO₃ (BT) introduces a promising paradigm for multifunctional applications. This study delves into the structural, magnetic, and dielectric characteristics of Ba_1−xCe_xTiO₃ (BCT) ceramics with Ce substitution varying from 0 to 2%. Notably, BT in its pristine state exhibited weak ferromagnetism at a lower applied magnetic field. However, the introduction of Ce³⁺ led to an augmentation in the M_s values, attributed to the elevated presence of oxygen vacancies. Rietveld analysis of the X-ray diffraction patterns and the Raman spectra of all the samples revealed the unaltered tetragonal structure of BT despite increasing the Ce content to 1.5%. Simultaneously, an increase in the unit cell volume and crystalline size was noted, whereas the tetragonality factor (c/a) diminished with increasing Ce substitution. Field emission scanning electron microscopy (FESEM) analysis highlighted a transition in the average grain size from 738 nm to 899 nm with increasing Ce content. The investigation of dielectric properties showed a proportional reduction in the dielectric constant with increasing Ce concentration. Additionally, dielectric measurements revealed that AC conductivity increased with frequency, and Ce doping further enhanced the conductivity by introducing additional charge carriers. Despite the reduction in the dielectric constant, the minimal dielectric loss made these materials highly suitable for high-frequency applications. This study underscores the significance of Ce incorporation into BT, introducing magnetic behaviour to an otherwise non-magnetic, lead-free BT system. The observed phenomena open avenues for exploring previously limited multiferroic and magnetoelectric properties of BT ceramics, a promising direction in the realm of lead-free ferroelectrics.