Improvement of quality factor of SrTiO₃ dielectric ceramics with high dielectric constant using Sm₂O₃

Abstract

The ceramics with the formula of Sr 1−x Sm 2x/3 TiO 3 (x = 0-0.5) were prepared by conventional ceramic process. A single phase of SrTiO 3 -type with cubic perovskite structure was found companied with a decrease in crystal volume when x < 0.5, which was confirmed by X-ray diffraction results and Rietveld refine. At the level of x = 0.5, the sample consisted of two phases of SrTiO 3 -type and Sm 2 Ti 2 O 7 . Raman spectra were used to confirm the change of vibration to explain the variation in microwave dielectric properties. The dielectric constant decreased, the quality factor increased, and the temperature coefficient shifted negatively, when the x value increased from 0 to 0.4. When the x value located between 0.3 and 0.4, the ceramics exhibited high dielectric constant of 140-152, high quality factor (>6000). K E Y W O R D Smicrowave dielectric, quality factor, Raman, SrTiO 3

Novel thermally stable, high quality factor Ba4(Pr0.4Sm0.6)28/3Ti18−yGa4y/3O54 microwave dielectric ceramics

“…In consideration of microwave region, the real and imaginary part of microwave permittivity can be obtained by Equations (8) and (9): which are shown in Figure 4B. The ε ∞ can be calculated from the infrared region at 4000 cm −1 by Equation 6. The parameters of all phonon modes are listed in Table 3.…”

“…In decades, due to the rapid development of wireless technology, the microwave components play an important role in the field of the fifth‐generation (5G) mobile communication, global positioning system, wireless fidelity, and so on . As the key materials, the microwave ceramics should possess high microwave dielectric constant ( ε r ), high quality factor (Qf) ( Q = ), and near‐zero TCF (temperature coefficient of resonant frequency) …”

“…[1][2][3] As the key materials, the microwave ceramics should possess high microwave dielectric constant (ε r ), high quality factor (Qf) (Q = 1 tan ), and near-zero TCF (temperature coefficient of resonant frequency). [4][5][6][7][8] Ba 6−3x Pr 8+2x Ti 18 O 54 (x = 2/3) ceramic with tungsten bronze type structure has been widely researched for its high dielectric constant (ε r > 90). However, the commercial value has affected greatly by the large positive TCF value of +150 ppm/°C and relatively low-Qf (~6000 GHz).…”

Recent progress of graphene‐based materials for efficient charge transfer and device performance stability in perovskite solar cells

“…Having slightly higher electron mobility (5‐8 cm 2 V −1 s −1 ) and higher CBM as compared with TiO 2 , make SrTiO 3 another potential ETM. In addition, SrTiO 3 has high dielectric constant, 135 which could inhibit the recombination at the ETL/perovskite interface, but the reported device efficiency is still low and needs to be improved. Besides bulk electron mobility (240 cm 2 V −1 s −1 ), SnO 2 shows better stability because of its high transparency in the UV light range 136 .…”

High-efficiency and ultra-thin electromagnetic wave absorption xAl2O3–(1 − x)Sr0.85Gd0.15TiO3 ceramics in X-band

“…Therefore, the dielectric properties of SrTiO 3 ceramic depend not only on the synthesis process and particle size, but also on the doping element kind and amount [15]. In order to enhance the microwave absorbing property of SrTiO 3 , various transition metals and rare earth ions were used as dopants [16,17].…”