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LiZnTi (Li0.43Zn0.27Ti0.13Fe2.17O4) ferrites doped with 0.35 wt. %–1.5 wt. % H3BO3-Bi2O3-SiO2-ZnO (BBSZ) were synthesized through a low temperature ceramic sintering process. The grain growth of LiZnTi ferrites was discussed by using the liquid phase sintering mechanism. BBSZ promoted grain growth via liquid phase sintering, and the optimum addition of BBSZ could reduce porosity of the sample. Meanwhile, selected parameters including saturation induction (BS), coercivity (HC) and ferromagnetic resonance line width (ΔH) were measured as functions of doping content, and their relationships with ferrite porosity and microstructure were also discussed. The LiZnTi ferrite samples containing x = 0.5, 0.65, and 0.8 sintered at 920 °C, 900 °C, and 880 °C, respectively, exhibited high BS and low ΔH values at 9.3 GHz. The addition of proper content of BBSZ can not only improve BS but also reduce HC and ferromagnetic resonance line width (ΔH) by low temperature (∼900 °C) liquid phase sintering.

NiZn ferrite nanoparticles (2−20 wt %) of composition Ni 0.4 Zn 0.6 Fe 2 O 4 were introduced into LiZnTi ferrite of composition Li 0.42 Zn 0.27 Ti 0.11 Fe 2.2 O 4 and sintered at a temperature of 920°C for 2 h, well below that of the Ag melting point. Here, LiZnTi ferrites were prepared by a solidstate reaction method, and NiZn ferrite nanoparticles were fabricated by a hydrothermal chemical technique at 180°C. A low ferromagnetic resonance (FMR) line width, low coercivity, and high magnetic moment were achieved after refinement of the heat treatment conditions of the mixture. Riveted full profile refinement of the X-ray powder diffraction patterns and analysis of Mossbauer spectra were employed to study the structure and caption distribution. The results confirm a pure spinel phase after processing. A narrow FMR line width of 152.5 Oe, a reduced coercivity of 132.9 A/m, and an improved saturation magnetization of 74.23 emu/g were obtained by way of the addition of 8 wt % NiZn ferrite nanoparticles.

LiZn ferrite ceramics with high saturation magnetization (4πM) and low ferromagnetic resonance line widths (ΔH) represent a very critical class of material for microwave ferrite devices. Many existing approaches emphasize promotion of the grain growth (average size is 10-50 μm) of ferrite ceramics to improve the gyromagnetic properties at relatively low sintering temperatures. This paper describes a new strategy for obtaining uniform and compact LiZn ferrite ceramics (average grains size is ∼2 μm) with enhanced magnetic performance by suppressing grain growth in great detail. The LiZn ferrites with a formula of LiZnMnTiFeO were prepared by solid reaction routes with two new sintering strategies. Interestingly, results show that uniform, compact, and pure spinel ferrite ceramics were synthesized at a low temperature (∼850 °C) without obvious grain growth. We also find that a fast second sintering treatment (FSST) can further improve their gyromagnetic properties, such as higher 4πM and lower ΔH. The two new strategies are facile and efficient for densification of LiZn ferrite ceramics via suppressing grain growth at low temperatures. The sintering strategy reported in this study also provides a referential experience for other ceramics, such as soft magnetism ferrite ceramics or dielectric ceramics.

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Germanium Tin (GeSn) films have drawn great interest for their visible and near-infrared optoelectronics properties. Here, we demonstrate large area Germanium Tin nanometer thin films grown on highly flexible aluminum foil substrates using low-temperature molecular beam epitaxy (MBE). Ultra-thin (10–180 nm) GeSn film-coated aluminum foils display a wide color spectra with an absorption wavelength ranging from 400–1800 nm due to its strong optical interference effect. The light absorption ratio for nanometer GeSn/Al foil heterostructures can be enhanced up to 85%. Moreover, the structure exhibits excellent mechanical flexibility and can be cut or bent into many shapes, which facilitates a wide range of flexible photonics. Micro-Raman studies reveal a large tensile strain change with GeSn thickness, which arises from lattice deformations. In particular, nano-sized Sn-enriched GeSn dots appeared in the GeSn coatings that had a thickness greater than 50 nm, which induced an additional light absorption depression around 13.89 μm wavelength. These findings are promising for practical flexible photovoltaic and photodetector applications ranging from the visible to near-infrared wavelengths.