Interface-Engineered Copper-Barium Strontium Titanate Composites with Tunable Optical and Dielectric Properties

Area of Science:

• Materials Science
• Ceramic Engineering
• Nanotechnology

Background:

• Barium strontium titanate (BST) is a prominent dielectric material.
• Enhancing BST properties for advanced applications is crucial.
• Ceramic-metal composites offer tunable multifunctional characteristics.

Purpose of the Study:

• To synthesize and characterize copper-reinforced BST ceramic composites.
• To investigate the effect of varying copper content on BST properties.
• To explore potential applications in high-capacitance decoupling.

Main Methods:

• Sol-gel synthesis of BST-Cu composites.
• Spark plasma sintering (SPS) for densification.
• X-ray diffraction, FT-IR, SEM, and electrical characterization.

Main Results:

• Coexistence of cubic and tetragonal BST phases with metallic Cu.
• Abnormal grain growth and Cu agglomeration observed.
• Optical bandgap reduced from 3.10 eV to 2.01 eV.
• Percolation threshold at ~30 wt% Cu for conductivity and permittivity.
• Maximum permittivity of ~1.2 × 10^5 at 1 kHz for BST-Cu30%.

Conclusions:

• BST-Cu composites demonstrate tunable dielectric and optical responses.
• Maxwell-Wagner interfacial polarization significantly enhances permittivity.
• Composites show promise for high-capacitance decoupling applications.
• Properties are dependent on Cu content and connectivity.