Enhanced Spectroscopic Insight into Acceptor-Modified Barium Strontium Titanate Thin Films Deposited via the Sol-Gel...

Area of Science:

• Materials Science
• Solid-State Physics
• Ceramic Engineering

Background:

• Barium strontium titanate (Ba_xSr_1-xTiO₃) is a key ferroelectric material with tunable dielectric properties.
• Composite materials offer enhanced performance by combining different material characteristics.
• Magnesium oxide (MgO) acts as a linear dielectric reinforcement in ferroelectric matrices.

Purpose of the Study:

• To investigate the effect of MgO addition on the structural and impedance properties of Ba_xSr_1-xTiO₃ thin films.
• To optimize the composition of Ba_xSr_1-xTiO₃-MgO composites for improved dielectric performance.
• To analyze the relaxation mechanisms in these composite thin films.

Main Methods:

• Sol-gel deposition of Ba_xSr_1-xTiO₃-MgO composite thin films on stainless steel substrates.
• Thermal treatment at 650 °C to achieve desired film properties.
• Impedance spectroscopy analysis using Kohlrausch-Williams-Watts function and electric equivalent circuit modeling.

Main Results:

• The incorporation of MgO (1-5 mol%) into Ba_xSr_1-xTiO₃ films influenced impedance response and relaxation behavior.
• Films with 3 mol% MgO showed the least stretched relaxation function (β values).
• Capacitance significantly increased from 2.97 × 10^-12 F to 5.78 × 10^-10 F with 3 mol% MgO addition.

Conclusions:

• MgO acts as an effective reinforcement in Ba_xSr_1-xTiO₃ thin films, modifying their dielectric properties.
• The optimal MgO concentration for enhanced capacitance was found to be 3 mol%.
• The observed non-Debye-type relaxation phenomena suggest complex charge carrier dynamics within the composite films.