Influence of Grain-Growth Inhibitors on Modified (Ba,Sr)(Sn,Ti)O₃ for Electrocaloric Application

Area of Science:

• Materials Science
• Solid State Chemistry
• Thermodynamics

Background:

• Perovskite materials like Ba$_{x}$Sr$_{1-x}$Ti$_{1-y}$Sn$_{y}$O$_{3}$ are crucial for advanced electronic applications.
• Controlling microstructure is key to optimizing dielectric, ferroelectric, and electrocaloric properties.
• Electrocaloric (EC) cooling offers a promising solid-state cooling technology.

Purpose of the Study:

• Investigate the impact of grain-growth inhibitors (MgO, Y$_{2}$O$_{3}$, MnCO$_{3}$) and Ca modification on BSSnT ceramics.
• Optimize the microstructure and electrocaloric performance of Ba$_{0.62}$Ca$_{0.20}$Sr$_{0.18}$Sn$_{0.065}$Ti$_{0.935}$O$_{3}$ (BCSSnT-20).
• Determine the effects of sintering temperature and time on BCSSnT-20 properties.

Main Methods:

• Synthesis and characterization of Ba$_{0.82}$Sr$_{0.18}$Sn$_{0.065}$Ti$_{0.935}$O$_{3}$ (BSSnT) with various additives.
• Microstructural analysis (grain size, homogeneity) of modified BSSnT and BCSSnT-20 ceramics.
• Measurement of dielectric, ferroelectric, and electrocaloric (EC) properties under varying electric fields and temperatures.

Main Results:

• Additives MgO, Y$_{2}$O$_{3}$, and MnCO$_{3}$ significantly reduced BSSnT grain size to below 1 µm.
• BCSSnT-20 exhibited a fine-grained microstructure (1.5 µm) and a maximum EC temperature change of 0.49 K at 40 °C.
• Optimizing sintering temperature for BCSSnT-20 increased grain size and EC temperature change, reaching 0.37 K at 20 °C (2 V/µm).

Conclusions:

• Ca modification and controlled microstructure are vital for enhancing electrocaloric effects in BSSnT ceramics.
• BCSSnT-20 demonstrates significant potential for applications in multilayer ceramic (MLC) components for EC cooling.
• Further optimization of sintering parameters can improve the electrocaloric performance of BCSSnT-20 for practical cooling devices.