Giant effect on structural, magnetic, electrical, and optical properties of lead-free Ba <sub>0.6</sub> Sr <sub>0.4</sub> Ti <sub>1-x</sub> Al <sub>x</sub> O <sub>3</sub> ceramics via Sr and Al Co-doping engineering
Hasan Mahmud, Jamal Uddin Ahamed, M. N. I. Khan
Abstract
Abstract In this research, structural, magnetic, electrical, and optical properties of Al 3+ substituted Ba 0.6 Sr 0.4 Ti 1-x Al x O 3 ceramics (where x = 0.00 to 0.20) have been investigated and discussed. The ceramic samples have been successfully synthesized by the conventional solid-state reaction method. The crystallinity of the prepared samples has been confirmed by x-ray peak broadening techniques such as the Williamson Hall (W-H) plot technique and the Scherrer method. The lattice constant ‘ a ’, showing a significant drop as Al concentration increases, varies from 3.942 Å to 3.921 Å. The FTIR spectrum revealed a prominent peak between 435 cm −1 to 540 cm −1 , without showing any secondary phase. Raman spectroscopic analysis showed that the prepared samples are in cubic phase with no phase transition. The shifting of a dominating peak in Raman at 580 cm −1 is due to the development of Al Ti defects. VSM analysis at room temperature showed the ferromagnetic characteristics of all the samples. The highest value of the anisotropic constant (Ka ∼ 39.933 emu cm −3 ) has been seen at x = 0.10. The real component of initial permeability is almost constant for the frequency range of about 75 MHz, and above this frequency range, it quickly reduces. At the high-frequency range, the prepared samples show an excellent relative quality factor due to the low dielectric loss, notably when x = 0.05. The prepared perovskites exhibited minimum eddy current loss characteristics due to the increment of AC resistivity at x = 0.20. UV–visible spectroscopy shows a significant change in the energy bandgap from 3.23 eV to 3.04 eV with the doping concentrations.