Good dielectric performance and broadband dielectric polarization in Ag, Nb co‐doped TiO₂

Abstract

Due to the demand of miniaturization and integration for ceramic capacitors in electronic components market, TiO2‐based ceramics with colossal permittivity has become a research hotspot in recent years. In this work, we report that Ag+/Nb5+ co‐doped (Ag1/4Nb3/4)xTi1−xO2 (ANTOx) ceramics with colossal permittivity over a wide frequency and temperature range were successfully prepared by a traditional solid–state method. Notably, compositions of ANTO0.005 and ANTO0.01 respectively exhibit both low dielectric loss (0.040 and 0.050 at 1 kHz), high dielectric permittivity (9.2 × 103 and 1.6 × 104 at 1 kHz), and good thermal stability, which satisfy the requirements for the temperature range of application of X9R and X8R ceramic capacitors, respectively. The origin of the dielectric behavior was attributed to five dielectric relaxation phenomena, i.e., localized carriers' hopping, electron–pinned defect–dipoles, interfacial polarization, and oxygen vacancies ionization and diffusion, as suggested by dielectric temperature spectra and valence state analysis via XPS; wherein, electron‐pinned defect–dipoles and internal barrier layer capacitance are believed to be the main causes for the giant dielectric permittivity in ANTOx ceramics.

Improved microstructure and significantly enhanced dielectric properties of Al3+/Cr3+/Ta5+ triple-doped TiO2 ceramics by Re-balancing charge compensation

“…3, the grain shape of all the ceramics exhibited a relatively similar shape. Numerous small-sized pores in the CTTO ceramic are observed even when the ceramic was sintered at a temperature as high as 1450 C for 5 h. This observation is in contrast to those reported in other co-doped TiO 2 systems, 9,10,20,21,25,35 which for a highly dense microstructure is usually obtained when sintering at high temperatures >1400 C. This result indicates that the Cr 3+ and Ta 5+ dopants inhibited the sintering (or densication) rate of the TiO 2 ceramic. Usually, the sintering rate of polycrystalline ceramic oxides is dependent on the diffusion rate of ions.…”

“…Such a large 3 0 of ACTTO-2 can be comparable to those observed in several co-doped TiO 2 ceramics. 5,8,9,13,14,21,22,25,[27][28][29]35,38 Furthermore, the rapid decrease in 3 0 is observed at the frequency range of 10 4 Hz, indicating the additional polarization in the low-frequency range below 10 4 Hz. This result is caused by the replacement of a half Cr 3+ with Al 3+ ions.…”

“…Recently, a large number of accepter/donor co-doped TiO 2 ceramics have been widely investigated due to a potential application in ceramic capacitors such as In 3+ /Nb 5+ , 1-4 Al 3+ / Nb 5+ , [5][6][7] Ga 3+ /Nb 5+ , 8,9 Sc 3+ /Nb 5+ , 10 Fe 3+ /Nb 5+ , 11,12 Er 3+ /Nb 5+ , 13,14 Zn 2+ /Nb 5+ , 15,16 Dy 3+ /Nb 5+ , 17 Gd 3+ /Nb 5+ , 18 Mg 2+ /Nb 5+ , 19,20 Ag + / Nb 5+ , 21,22 Li + /Nb 5+ , 23 Pr 3+ /Nb 5+ , 24 Ga 3+ /Ta 5+ , 25 Al 3+ /Ta 5+ , 26 Mg 2+ / Ta 5+ , 27,28 Co 2+ /Nb 5+ , 29 and Bi 3+ /Sb 5+ (ref. 30) co-doped TiO 2 ceramics.…”

The Primary Origin of Excellent Dielectric Properties of (Co, Nb) Co-Doped TiO2 Ceramics: Electron-Pinned Defect Dipoles vs. Internal Barrier Layer Capacitor Effect

“…The intensive investigation of a novel giant dielectric oxide (GDO) showing a high dielectric constant (ε′) has fueled research in the field of dielectric materials [ 1 , 2 , 3 , 4 , 5 , 6 ]. The loss tangent (tanδ) is also an essential factor for capacitor applications.…”

Ultrahigh Permittivity, Ultralow Loss and Stability in (In0.5Ta0.5)0.1Ti0.9O2 Ceramics With Temperature Range From -100 to 235 °C

“…In 2017, the (In 0.5 Ta 0.5 ) x Ti 1−x O 2 ceramics were discussed by Hu et al, and the result of the system exhibited excellent dielectric properties with temperature stability from -223 -127°C for x = 0.005 [13]. Plenty of researches paid attention to the capacitance, loss parameters and others of TiO 2 -based ceramics [14][15][16][17][18][19][20][21], but these reported materials which were di cult to balance permittivity, dielectric loss and temperature stability, especially further satisfy the requirements for high temperature industrial application above 150°C.…”