Phase evolution and microwave dielectric properties of novel LiAl5−xZnxO8−0.5x‐based (0 ≤ x ≤ 0.5) ceramics.

Novel LiAl5−xZnxO8−0.5x microwave dielectric ceramics were synthesized through a solid‐state reaction route. Phase evolution of LiAl5−xZnxO8−0.5x was determined by XRD analysis. The XRD results indicated that the phase compositions had a P4332 space group when 0 ≤ x ≤ 0.2 and a spinel structure when 0.3 ≤ x ≤ 0.5. The dielectric constant (εr) of this series' solid solutions decreased with the increase in Zn doping content, which was in good agreement with the Clausius‐Mossotti relation. Oxygen vacancy and the decreased degree of order degraded the quality factor (Q × f) of the two structures. The deterioration in quality factor was further verified by impedance spectroscopy. The temperature coefficient of the resonant frequency (τf) decreased with the increase in x and was correlated with the unit cell volume. Finally, CaTiO3 was used as a compensation material to obtain a near‐zero τf of the LiAl5O8 ceramic. [ABSTRACT FROM AUTHOR]