Enhanced microwave dielectric properties of Ba0.4Sr0.6TiO3 ceramics doping by metal Fe powders

Abstract

Ba0.4Sr0.6TiO3 ceramics by adding mental Fe powders have been fabricated via the solid-state reaction method. The microstructures and optical properties of samples are systematically studied in order to establish the effects of Fe powder additives on microwave dielectric properties of Ba0.4Sr0.6TiO3 ceramics by x-ray diffraction, x-ray photoelectron spectroscopy, and optical reflective spectrum. The results show the coexistence of Fe2+ and Fe3+ in Ba0.4Sr0.6TiO3 ceramics, the decrease of O vacancy concentrations, and their incorporation into the B-site (Ti) of the Ba0.4Sr0.6TiO3 host lattice give rise to excellent microwave dielectric properties. All samples have a higher Q value above 290 while maintaining relatively high tunability above 16.6%. In particular, the sample with the composition of x = 0.035 mol has the dielectric constant of 889, Q × f value of 826 (at 1.370 GHz), and tunability of 24%, which are very promising for high power tunable devices. In comparison, Fe2O3 oxide doped Ba0.4Sr0.6TiO3 ceramics with the same molar ratios of Fe exhibit inferior microwave properties. It indicates that additives of the metal Fe powders can more effectively improve dielectric properties of BaxSr1-xTiO3 system than Fe2O3 oxide.

Oxygen vacancy-related dielectric relaxation and electrical conductivity in La-doped Ba(Zr0.9Ti0.1)O3 ceramics

“…The significant blue-shift for different samples is mainly resulted from the addition of La ion. The mechanism for the blue-shift phenomenon contributes to lattice distortion and oxygen vacancy concentration [41]. Consequently, in the materials belonging to doublyionized oxygen vacancies, the long range motion of doubly-ionized oxygen vacancies leads to Dc electrical conduction [22].…”

Significantly enhanced dielectric constant and energy storage properties in polyimide/reduced BaTiO3composite films with excellent thermal stability

“…The observed XPS spectra of BaTiO 3 and rBaTiO 3 were consistent with the reported data in literature. 48,49 The Ti 2p peak of BaTiO 3 was split into 4 peaks, which were located at 465.0 eV and 459.8 eV corresponding to Ti 2p3/2 and Ti 2p3/2 peaks of Ti 4+ , and 463.9 eV and 458.26 eV corresponding to Ti 2p1/2 and Ti 2p1/2 peaks of Ti 3+ , respectively. 50 The Ti 2p peak of rBaTiO 3 can also be deconvoluted into 4 peaks, two of which were located at 464.4 eV and 459.3 eV consistent with the Ti 2p3/2 peaks of Ti 4+ , and the other two peaks were located at 463.5 eV and 458.1 eV, corresponding to the Ti 2p1/2 peaks of Ti 3+ .…”

Performance Enhancement of the Dielectric Properties of Sn-Doped Ba0.8Sr0.2TiO3 Perovskite

“…8 BST is used in different applications, such as dynamic random access memories, tunable phase shifters and tunable microwave devices. [9][10][11][12][13] Many studies have been carried out on the substitution in the B site. Some of them have reported on the influence of the substitution of Sn 4+ ions for Ti 4+ ions.…”