Effect of Cu2+ substitution on the crystal structure, bond properties, and microwave performance of ZnTiNb2O8 ceramics

Effect of composite methods on the phase transition and microwave performances of ZnZrNb1.99(Sn0.5W0.5)0.01O8–TiO2 system

“…For the crystal structure of ZnTiNb 2 O 8 , the Zn 2+ /Ti 4+ /Nb 5+ cation occupies the 4c Wyckoff position, while the O 2− anion occupies the 8f Wyckoff position. Zn 2+ /Ti 4+ /Nb 5+ cations are all surrounded by six oxygen anions, forming tightly bound [Zn/Ti/NbO 6 ] octahedra 6 . With the further increase of TiO 2 content (0.50 ⩽ y ⩽ 0.56, area III), the ixiolite phase accompanied with a secondary rutile phase of Zn 0.15 Nb 0.3 Ti 0.55 O 2 (JCPDS 79–1186) can be determined.…”

“…The surface and cross‐sectional Raman spectra of the ceramics were analyzed by a Raman spectroscope (Renishaw, InVia Reflex, 532 nm) The spectral test range is 50–1100 cm −1 . The microwave dielectric performances of the samples were measured using the Hakki‐Coleman technique 6 and an Agilent vector network analyzer (8720 ES) 7 . The τ f value was calculated using the equation below 6,7 : $$$$\begin{equation}{\tau _{\rm{f}}}\left( {\frac{{{\rm{ppm}}}}{{^\circ {\rm{C}}}}} \right) = \frac{{{f_1} - {f_0}}}{{\left( {{T_1} - {T_0}} \right){f_0}}} \times {10^6}\left( {\frac{{{\rm{ppm}}}}{{^\circ {\rm{C}}}}} \right)\end{equation}$$$$where f 0 and f 1 represented the resonant frequency at T 0 (25°C) and T 1 (85°C), respectively.…”

“…Over the last few decades, microwave dielectric ceramics (MWDCs) have been steadily developed for various microwave components in commercial wireless communication technology systems, such as filters, resonators, and antennas 1–5 . It is well known that in order to meet the practical application requirements of miniaturization, frequency selectivity, and high temperature stability of microwave devices, MWDCs need to have a relatively high dielectric constant ($${\varepsilon _{\rm{r}}} > 20$$), a high quality factor ( Q × f , Q $$ = 1/{\rm{tan}}\delta $$), and a near‐zero temperature coefficient of resonant frequency ($${\tau _{\rm{f}}} = \pm 10{\rm{ppm}}/^\circ {\rm{C}}$$) 6,7 …”

Enhancement of superior dielectric performance in ZnTiNb2O8 systems by multi‐layer architecture

“…9,10 Among them, ZnTiNb 2 O 8 is one of the most promising compositions since it possesses the highest Q×f value among all published values for the ATiNb 2 O 8 system (𝜀 𝑟 = 33.91, Q×f = 64,136 GHz, and 𝜏 𝑓 = −50.57 ppm/ • C). 9 It can be used in some microelectronic technologies, such as microwave integrated circuit substrates and gate dielectrics if its negative 𝜏 𝑓 value is modified to be near to zero. According to the literatures, rutile TiO 2 is a well-known chemical with a positive 𝜏 𝑓 value (𝜏 𝑓 = +465 ppm/ • C) that has been frequently used as a high-temperature stable 𝜏 𝑓 tailor.…”

“…It is made up of closely packed oxygen layers with cations occupying one-half of the octahedral gaps. 9,[17][18][19] As a result of the structural similarity between ZnTiNb 2 O 8 with ixiolite structure and TiO 2 with rutile structure, we are motivated to investigate the relationship between phase structure and dielectric properties in Zn 0.995 Cu 0.005 TiNb 2 O 8 @xTiO 2 (x = 0.00-0.55, in volume fraction) ceramics in this work, which is also one of the focuses of this study; (2) laminated co-firing process, in which two materials with opposite 𝜏 𝑓 values are stacked in a certain order, thus synthetically modulating the microwave dielectric properties of the specimen. [20][21][22] For example, Zhang et al 23 demonstrated that Zn In this work, Zn 0.995 Cu 0.005 TiNb 2 O 8 is used as an object to deeply analyze and compare the effects of random distribution and laminated co-firing processes on the microwave dielectric properties of ceramics.…”