Upconversion photoluminescence and dielectric properties in Er3+ and Yb3+ co-doped Sr4La2Ti4Nb6O30

(Co, Nb) co-doped rutile TiO2 (CoNTO) nanoparticles with low dopant concentrations were prepared using a wet chemistry method. A pure rutile TiO2 phase with a dense microstructure and homogeneous dispersion of the dopants was obtained. By co-doping rutile TiO2 with 0.5 at.% (Co, Nb), a very high dielectric permittivity of ε′ » 36,105 and a low loss tangent of tanδ » 0.04 were achieved. The sample–electrode contact and resistive outer-surface layer (surface barrier layer capacitor) have a significant impact on the dielectric response in the CoNTO ceramics. The density functional theory calculation shows that the 2Co atoms are located near the oxygen vacancy, creating a triangle-shaped 2CoVoTi complex defect. On the other hand, the substitution of TiO2 with Nb atoms can form a diamond-shaped 2Nb2Ti complex defect. These two types of complex defects are far away from each other. Therefore, the electron-pinned defect dipoles cannot be considered the primary origins of the dielectric response in the CoNTO ceramics. Impedance spectroscopy shows that the CoNTO ceramics are electrically heterogeneous, comprised of insulating and semiconducting regions. Thus, the dielectric properties of the CoNTO ceramics are attributed to the interfacial polarization at the internal insulating layers with very high resistivity, giving rise to a low loss tangent.

Download Full-text

Effects of co-doped CaO/MnO on the piezoelectric/dielectric properties and phase transition of lead-Free (Bi0.5Na0.5)0.94Ba0.06TiO3 piezoelectric ceramics

Journal of Electroceramics ◽

10.1007/s10832-008-9548-5 ◽

2008 ◽

Vol 23 (2-4) ◽

pp. 564-571 ◽

Cited By ~ 8

Author(s):

Man-Soon Yoon ◽

Young-Geun Lee ◽

Soon-Chul Ur

Keyword(s):

Phase Transition ◽

Dielectric Properties ◽

Piezoelectric Ceramics ◽

Lead Free ◽

Co Doped

Download Full-text

Ferroelectric relaxor behavior and dielectric properties of La/Y co-doped (Ba0.9Ca0.1)(Zr0.2Ti0.8)O3 ceramics

Journal of Materials Science Materials in Electronics ◽

10.1007/s10854-016-4542-1 ◽

2016 ◽

Vol 27 (6) ◽

pp. 6150-6155 ◽

Cited By ~ 2

Author(s):

Anqi Li ◽

Yu Wang ◽

Liu Yang ◽

Ping Yang ◽

Gang Wang ◽

...

Keyword(s):

Dielectric Properties ◽

Relaxor Behavior ◽

Ferroelectric Relaxor ◽

Co Doped

Download Full-text

Upconversion photoluminescence properties of Ho3+/Yb3+ co-doped YNbO4 powder

Optical Materials ◽

10.1016/j.optmat.2017.07.001 ◽

2018 ◽

Vol 75 ◽

pp. 68-73 ◽

Cited By ~ 7

Author(s):

Chunhui Niu ◽

Leiwei Li ◽

Xiaoying Li ◽

Yong Lv ◽

Xiaoping Lang

Keyword(s):

Photoluminescence Properties ◽

Upconversion Photoluminescence ◽

Co Doped

Download Full-text

Structure, Defects and Microwave Dielectric Properties of Al-doped and Al/Nd Co-doped Ba4Nd9.33Ti18O54 Ceramics

10.21203/rs.3.rs-783511/v1 ◽

2021 ◽

Author(s):

Weijia Guo ◽

Zhiyu Ma ◽

Yu Luo ◽

Yugu Chen ◽

Zhenxing Yue ◽

...

Keyword(s):

Dielectric Properties ◽

Resonant Frequency ◽

Microwave Dielectric Properties ◽

Relative Dielectric Constant ◽

Doping Amount ◽

Solid State Method ◽

Depolarization Current ◽

Structure Defects ◽

Microwave Dielectric ◽

Co Doped

Abstract Ba4Nd9.33Ti18-zAl4z/3O54 (BNT-A, 0 ≤ z ≤ 2) and Ba4Nd9.33+z/3Ti18-zAlzO54 (BNT-AN, 0 ≤ z ≤ 2) ceramics were prepared by solid state method, and the effects of the two doping methods on microwave dielectric properties were compared. As the doping amount z increased, the relative dielectric constant (εr) and the temperature coefficient of resonant frequency (τf) values of the ceramics decreased, and the quality factor (Q, usually expressed by Q×f, where f is the resonant frequency) of the ceramics obviously increased when z ≤ 1.5. With the same z value, the εr and Q×f values of Al/Nd co-doped ceramics are both higher than those of Al-doped ceramics. Rietveld refinement, Raman spectroscopy and thermally stimulated depolarization current (TSDC) technique were applied to clarify the relationship among the structure, defects and microwave dielectric properties. It is shown that the Q×f values of those ceramics were closely related to the strength of the A-site cation vibration and the concentration of oxygen vacancies (B). Excellent microwave dielectric properties of εr = 72.2, Q×f = 16480 GHz, and τf = +14.3 ppm/℃ were achieved in BNT-AN ceramics with z = 1.25.

Download Full-text