TY  - JOUR
AU  - Li, Wenyuan
AU  - Xian, Yue
AU  - Deng, Hanao
AU  - Xu, Jianan
AU  - Wei, Yaxin
AU  - Chang, Aimin
AU  - Zhang, Bo
PY  - 2025
TI  - Sc3+-modified Mg–Al–Mn–Fe–O spinel ceramics with co-enhanced microwave dielectric and thermosensitive properties for multifunctional applications
JO  - Journal of Advanced Ceramics
SN  - 2226-4108
SP  - 9221153
VL  - 14
IS  - 10
AB  - With the rapid development of communication technology, multifunctional ceramics that integrate microwave dielectric and negative temperature coefficient (NTC) thermistor properties have met the evolving needs of electronic components. Although conventional spinel oxides excel in single functionalities, they struggle to simultaneously achieve linear NTC behavior and stable microwave dielectric performance over a wide temperature range. To address this, the role of Sc3+ substitution in modifying Mg0.8Mn0.2Al1.6Fe0.4O4 ceramics was systematically investigated. The results demonstrate that Sc3+ substitution effectively inhibits oxygen vacancy formation and achieves the ratio regulation of the Mn2+/Mn3+ and Fe3+/Fe2+ bimetallic redox pairs, which significantly improves the material constant B (B200/1000°C = 8367–9758 K) and enables linear resistance–temperature curves (lnρ–1000/T) within a broad temperature range (200–1000 °C). Additionally, the ceramics exhibit optimal microwave dielectric properties: low dielectric constants (εr = 8.86–10.55), ultrahigh quality factors (Q∙f = 96,000–149,000 GHz), and near-zero temperature coefficients of resonant frequency (τf = −33.2×10−6 to −10.2×10−6 °C−1), resulting from Sc3+-induced lattice stabilization and octahedral bond-valence strengthening effects. A cylindrical dielectric resonator antenna (CDRA) fabricated from Mg0.8Mn0.2Al1.3Sc0.3Fe0.4O4 achieves 92% radiation efficiency and 6.28 dBi gain at 12 GHz, validating its potential for Ku-band satellite communication. This work reveals that Sc3+ substitution synergistically enhances both the microwave dielectric and thermosensitive functionalities of Mg–Al–Mn–Fe–O spinel ceramics, offering a breakthrough in material design for next-generation multifunctional communication devices.
UR  - https://doi.org/10.26599/JAC.2025.9221153
DO  - 10.26599/JAC.2025.9221153