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Tunable Microwave Dielectric Properties in Rare-Earth Niobates via a High-Entropy Configuration Strategy To Induce
Deqin Chen1, Xiaowei Zhu1, Siyu Xiong1
1Guangxi University Key Laboratory of Non-ferrous Metal Oxide Electronic Functional Materials and Devices, College of Material Science and Engineering, Guilin University of Technology, Guilin 541004, China.
ACS Applied Materials & Interfaces
|November 6, 2023
Summary
High-entropy ceramics with varying Vanadium content were synthesized to achieve stable dielectric properties. This study demonstrates an effective method for tuning dielectric loss and temperature stability in rare-earth niobate ceramics.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Ceramic Engineering
Background:
- Rare-earth niobate (LnNbO4) ceramics are crucial for microwave dielectric applications.
- Achieving temperature stability and low dielectric loss simultaneously is challenging.
- High-entropy strategies offer a novel approach to tune material properties.
Purpose of the Study:
- To synthesize and characterize (La0.2Nd0.2Sm0.2Ho0.2Y0.2)(Nb1-xVx)O4 ceramics using a high-entropy strategy.
- To investigate the effect of Vanadium (V) substitution on crystal structure, microstructure, and dielectric properties.
- To explore the correlation between phase transitions and dielectric performance, aiming for near-zero temperature coefficients.
Main Methods:
- Solid-phase synthesis method for preparing high-entropy ceramics.
- X-ray diffraction (XRD), Scanning Electron Microscopy/Transmission Electron Microscopy (SEM/TEM), and Raman spectroscopy for structural and microstructural analysis.
- Dielectric property measurements, including permittivity (εr), quality factor (Q × f), and temperature coefficient of resonance frequency (τf).
Main Results:
- Phase transformation from monoclinic fergusonite to tetragonal scheelite and zircon phases observed with increasing V content (x).
- Ceramic at x = 0.25 showed excellent temperature stabilization (τf = -1.52 ppm/°C) with εr = 18.06 and Q × f = 56,300 GHz.
- Ceramic at x = 0.2 exhibited low dielectric loss (τf = -7.96 ppm/°C) with εr = 18.14 and Q × f = 65,200 GHz.
Conclusions:
- The combination of high-entropy strategy and Nb-V substitution effectively regulates the dielectric properties of LnNbO4 ceramics.
- Near-zero temperature coefficient of resonance frequency (τf) can be achieved by controlling phase transitions and material composition.
- These findings present a promising route for developing advanced microwave dielectric materials with tailored properties.
