Giant dielectric response and relaxation behavior in (Tm + Ta) co-doped TiO₂ ceramics

Abstract

Dielectric materials with huge dielectric constants are attracting attention due to the growing demand for microelectronics and high energy-storage devices. In this work, Tm + Ta co-doped TiO2 ceramics were...

Colossal Permittivity Characteristics of (Nb, Si) Co-Doped TiO2 Ceramics

“…A second circular arc and non-zero intercept with the real Z axis is observed in the high frequency region for the samples with x = 0 and x > 0, respectively. This behavior is similar to what is reported for CaCu 3 Ti 4 O 12 [32] and co-doped TiO 2 [2,13]. The arc at high frequency (/non zero intercept) is attributed to the response of the semiconductor component (grains), while the larger arc represents the response of electrically insulating component (grain-boundaries).…”

“…The room temperature relative permittivity (ε ) of pure TiO 2 is ~100, which is not suitable for practical energy storage applications. Interestingly, recent studies reported colossal relative permittivity (CP) for co-doped TiO 2 in the form (A, B) x Ti 1−x O 2 , where A is pentavalent and B is tri-or bivalent cations [2][3][4][5][6]. The origin of CP of the co-doped TiO 2 ceramics is controversially discussed in the literature.…”

“…Therefore, CP and low tanδ were expected for these co-doped TiO 2 . In addition to the EPDD model, the internal barrier layer capacitance (IBLC) model [11,12] has also been suggested as a possible reason for the colossal permittivity of (donor, acceptor) co-doped TiO 2 [2,13]. The IBLC model is widely accepted for the interpretation of CP of electrically heterogeneous ceramics.…”

Ultralow dielectric loss in Tb + Ta‐modified TiO2 giant dielectric ceramics via designing defect chemistry

“…For heterogeneous ceramics, double (back-to-back) Schottky barriers are formed at the interfaces between n-type grains, leading to a bending of the conducting band at the grain boundaries, which results in a Φ b . 5,24 Under DC bias, the potential becomes unbalanced, resulting in an increase in reverse Φ b and a decrease in forward Φ b , as shown in Figure 9D. This may result in a large amount of space charge across the grain boundary barrier, resulting in an increase in ε r and tan δ.…”

“…Materials with large dielectric constants ( ε r > 10 3 ) are receiving increasing focus, due to their use in manufacturing capacitors, thermoelectric, and photoelectric sensors 1–3 . However, the high tan δ and sensitivity temperature/frequency stability of CP materials limit their widespread use in industry, and there is controversy over the origin and mechanism of CP 4–6 . Therefore, CP materials have been a hot topic of focus for researchers.…”