Structure, defects, and microwave dielectric properties of Al-doped and Al/Nd co-doped Ba4Nd9.33Ti18O54 ceramics

Abstract Low-loss tungsten-bronze microwave dielectric ceramics are materials with potential application value for miniaturized filters and antennas in the fifth-generation (5G) communication technology. In this work, a novel Al/Nd co-doping method of Ba 4 Nd 9.33 Ti 18 O 54 (BNT) chemical formula 9.33+ z /3 18− Al (BNT-AN, 0 ⩽ 2) was proposed to improve properties through structural defect modulation. Together Al-doped (Ba , BNT-A, comparison, were prepared by solid state method. It is found that has significant effect on improving compared doping. As doping amount increased, relative constant ( ε r ) temperature coefficient resonant frequency τ f decreased, Q×f values obviously increased when 1.5. Excellent = 72.2, 16,480 GHz, +14.3 ppm/°C achieved BNT-AN 1.25. Raman spectroscopy thermally stimulated depolarization current (TSDC) technique firstly combined analyze structures defects ceramics. shown improvement originated from decrease strength A-site cation vibration concentration oxygen vacancies $${\rm{V}}_{\rm{O}}^{ \cdot }$$ V O ⋅ ), demonstrating mechanism underlying modulation performance