Low‐Dielectric Loss Characteristics of Nd(Co_1/2Ti_1/2)O₃ Ceramics at Microwave Frequencies

Abstract

The microwave dielectric properties and the microstructures of Nd(Co1/2Ti1/2)O3 (NCT) ceramics using starting powders of Nd2O3, CoO, and TiO2 prepared by the conventional solid‐state route have been researched. The dielectric constant values (ɛr) saturated at 24.8–27. Quality factor (Q×f) values of 37 900–140 000 (at 9 GHz) and the measured τf values ranging from −45 to −48 ppm/°C can be obtained when the sintering temperatures are in the range of 1410°–1500°C. The ɛr value of 27, the Q×f value of 140 000 (at 9 GHz) and the τf value of −46 ppm/°C were obtained for NCT ceramics sintered at 1440°C for 4 h. For applications of high selective microwave ceramic resonator, filter, and antenna, NCT is proposed as a suitable material candidate.

Microwave characteristics of high-Q ZnO-doped Nd(Co1/2Ti1/2)O3 dielectric ceramics

“…Additionally, since the ionic radius of Co +2 (0.082 nm) is similar to that of Mg +2 (0.078 nm), the Mg +2 ion can be substituted by the ion of Co +2 to form Nd(Co 1/2 Ti 1/2 )O 3 . It also has suitable and optimum microwave dielectric properties (ε r ∼ 27, Q × f ∼ 140,000 GHz, f ∼ −46 ppm/ • C at a sintering temperature of 1440 • C) for applications in dielectric resonators [12]. However, the sintering temperatures of conventional microwave dielectric ceramics used in dielectric resonators, filters and other communication devices is typically 1200-1400 • C. For practical applications, the sintering temperature of Nd(Co 1/2 Ti 1/2 )O 3 ceramics must be reduced.…”

Influence of cooling rate on the structure and microwave dielectric properties of Nd(Zn1/2Ti1/2)O3 ceramics

“…Compared with the above mentioned systems, several double perovskite ceramics Ln(B 1/2 Ti 1/2 )O 3 (Ln¼ La, Nd, and Sm; B ¼ Zn, and Co) have drawn considerable attention in recent years due to their excellent microwave dielectric properties, especially ultrahigh quality factor (37,000-170,000 GHz) [8][9][10][11][12][13]. Among these materials, Nd(Zn 1/2 Ti 1/2 ) O 3 ceramics were found to possess better microwave dielectric properties (ε r =31.6, Q Â f=170000 GHz and τ f = À 42 ppm/ o C) after sintering at 1330 1C for 4 h with a cooling rate of 10 1C/ min [9].…”

Crystal structure and dielectric properties of La(Mg0.5Ti0.5)O3–Ca0.8Sm0.4/3TiO3 solid solution system at microwave frequencies

“…Several complex perovskites ceramics A(B 2+ 1/2 B 4+ 1/2 )O 3 (where A = La, Nd, Sm; B 2+ = Mg, Zn, Co, Ni, Mn; B 4+ = Ti and Sn) have been reported due to their excellent microwave dielectric properties [1,[7][8][9][10][11]. Among them, La(Mg 0.5 Ti 0.5 )O 3 has a high dielectric constant (ε r ∼ 29), a high quality factor (Q × f value ∼75,500 GHz) and a negative f value (−65 ppm/ • C) [12,13].…”