Studies of structural, electrical and ferroelectric characteristics of gadolinium and yttrium modified bismuth ferrite.

This communication mainly discusses the effect of Fe-site substitution of gadolinium (Gd) and yttrium (Y) on structural, dielectric, electrical and ferroelectric properties of bismuth ferrite (BiFeO 3). The Gd and Y modified bismuth ferrite of chemical compositions, Bi(Fe 0.9 Gd 0.1)O 3 (referred as BFGO10) and Bi(Fe 0.9 Y 0.1)O 3 (referred as BFYO10) has been prepared through a high-temperature solid-state-reaction method. Preliminary structural analysis has been performed by using X-ray diffraction data and pattern of BFGO10 and BFYO10, which show the structural transformation from the rhombohedral to orthorhombic symmetry. Structural analysis confirms a little suppression of impurity phases in the bismuth ferrite, which has been eliminated by the substitution (small amount 10%) of Gd and Y at its Fe-site. The average crystallite size of Gd and Y-modified BFO, evaluated with the help of Scherrer's relation, is found to be 45 nm and 42 nm respectively. The field emission scanning electron microscopy (FESEM) image reveals the formation of good quality samples along with proper and uniform distribution of grains. Detailed analysis of the impedance analyzer (LCR Meter) data, collected in a frequency range of (1–1000 kHz) at different temperatures (25–500 °C), exhibits the significant change in the dielectric, resistivity and capacitive features of the materials. The remnant polarization and coercivity are obtained through the polarization vs electric field (P-E loop) studies. The numerous other interesting information and important data obtained in this work may be utilized for device applications. • XRD data confirms crystal symmetry changes from rhombohedral to orthorhombic phase. • Higher dielectric permittivity (ϵ r) with small dielectric loss (tanδ) was achieved. • The dielectric relaxation process is non-Debye type. • Enhancement in the remnant polarization (P r) is observed. [ABSTRACT FROM AUTHOR]