Correlation of Phase Structure, Defect Relaxation, and Microwave Dielectric Properties in Low-Loss MgTiO Ceramic Systems.

Low-loss microwave dielectrics are of significant importance for the miniaturization and integration of microwave devices. In this paper, the ceramics of nominal composition MgTiO ( = 3-6) are synthesized, and the correlations among their phase compositions, defect behaviors, and microwave dielectric properties are systematically investigated. The analyses indicate that the MgTiO ceramics are a biphasic system consisting of hexagonal ilmenite-structured MgTiO and cubic spinel-structured MgTiO.

Identifying the Interfacial Polarization in Non-stoichiometric Lead-Free Perovskites by Defect Engineering.

Recent advances in perovskite ferroelectrics have fostered a host of exciting sensors and actuators. Defect engineering provides critical control of the performance of ferroelectric materials, especially lead-free ones. However, it remains a challenge to quantitatively study the concentration of defects due to the complexity of measurement techniques.

A First-Principles Study on the Multiferroic Property of Two-Dimensional BaTiO₃ (001) Ultrathin Film with Surface Ba Vacancy.

In this work, the multiferroic property of Ba-deficient BaTiO₃ (001) ultrathin film is studied employing the first-principles approach. The BaTiO₃ (001) ultrathin film is more energetically stable and behaves as a semiconductor relative to the (111) and (101) configurations, confirmed from the surface grand potential and electronic density of states. The electronic structures show that the O vacancy can switch the (001) film from a semi-conductor into a metal, while the Ba defect has a slight influence on the band gap, at a concentration of ~2.

Influence of W substitution on crystal structure, phase evolution and microwave dielectric properties of (NaBi)MoO ceramics with low sintering temperature.

In this work, the (NaBi)(MoW)O (x = 0.0, 0.5 and 1.

Epitaxially grown BaM hexaferrite films having uniaxial axis in the film plane for self-biased devices.

Barium hexaferrite (BaM) films with in-plane c-axis orientation are promising and technically important materials for self-biased magnetic microwave devices. In this work, highly oriented BaM films with different thickness and an in-plane easy axis (c-axis) of magnetization were grown on a-plane single-crystal sapphire substrates by direct current magnetron sputtering. A procedure involving seed layers, layer-by-layer annealing was adopted to reduce the substrate-induced strains and allow for the growth of thick (~3.

High and Temperature-Insensitive Piezoelectric Strain in Alkali Niobate Lead-free Perovskite.

With growing concern over world environmental problems and increasing legislative restriction on using lead and lead-containing materials, a feasible replacement for lead-based piezoceramics is desperately needed. Herein, we report a large piezoelectric strain (d*) of 470 pm/V and a high Curie temperature (T) of 243 °C in (NaK)NbO-(BiLi)TiO-BaZrO lead-free ceramics by doping MnO. Moreover, excellent temperature stability is also observed from room temperature to 170 °C (430 pm/V at 100 °C and 370 pm/V at 170 °C).

Structure, phase evolution, and microwave dielectric properties of (Ag0.5Bi0.5)(Mo0.5W0.5)O4 ceramic with ultralow sintering temperature.

In the present work, the microwave dielectric ceramic (Ag0.5Bi0.5)(Mo0.