Zhe Xiong

Different Additives Doped Ca–Nd–Ti Microwave Dielectric Ceramics with Distorted Oxygen Octahedrons and High Q × f Value

We investigated the structure and antireduction of Ti4+ in orthorhombic perovskite Ca0.61Nd0.26TiO3 (CNT) ceramic by doping with three different additives (Cr2O3, MnO2, and SnO2). The X-ray diffraction patterns showed that the main phase of orthorhombic perovskite was formed in all the samples. In addition, the substitution of M (M = Cr3+, Mn4+, Sn4+) for Ti4+ resulted in the oxygen octahedral distortion and changes of order degree of B-site, which was confirmed by Raman spectra. The εr and τf values were concerned with the average ionicity of B–O bond fi(B-ave) and the linear expansion coefficient α, respectively. The X-ray photoelectron spectra indicated that three different additives could restrain the reduction of Ti4+, which was beneficial to the improvement of the Q × f value for CNT ceramic. High Q × f value of 16 123 GHz was obtained in the CNT + 1 mol % Cr2O3 ceramic compared with Q × f value of 11 207 GHz in pure CNT ceramic.