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Metamaterials have drawn extensive attention for their fine regulation of electromagnetic waves at subwavelength scales. They have abundant electromagnetic modes, and support highly confined and enhanced electromagnetic fields on the surface which are highly sensitive to the surrounding dielectric environment, so they can be used in label-free optical biosensing. Compared with traditional optical biosensors, metamaterial biosensors have many advantages, such as miniaturization, integration, high sensitivity and multi-function customization. The recent progress of metamaterial biosensors in visible light and near infrared, middle infrared, and terahertz spectrums was summarized in this paper, including refractive index biosensing, surface-enhanced Raman scattering, surface-enhanced infrared absorption, and terahertz biosensing.

We deposited Fe-Ti-N magnetic films with a high sputtering power of 7 W/[cm.sup.2]. When the composition of the films was in the range of Fe--Ti(3.9 at.%)-N(8.8 at.%) to Fe-Ti(3.3 at.%)-N(13.5 at.%), the films were composed of [alpha]' and [Ti.sub.2]N precipitates. With the addition of nitrogen, 4[pi][M.sub.s] became higher than that of pure iron, reaching a maximum of 23.8 kG. At the same time, He was reduced to a minimum of 1.12 Oe. The best films can meet the needs of the recording head in dual-element giant magnetoresistive/inductive heads, yielding high storage density (10 Gb/[in.sup.2]). The incorporation of N in [alpha]-Fe brought about the [alpha]' phase with its higher saturation magnetization. Ti additions inhibited the equilibrium decomposition [alpha]' [right arrow] [alpha] + [gamma]' Because [H.sup.D.sub.C] [varies] [D.sup.6], where D is average grain diameter, grain size control is very important. The nitrogen induces severe distortion of the [alpha]' lattice, which can cause the grains to break into pieces and reduce the grain size. High sputtering power also led to the formation of fine grains, with diameter in the order of 14 nm. Probably [Ti.sub.2]N is preferentially precipitated on the grain boundary, pinning the grain boundary and stabilizing the grain size during high-temperature heat treatment. The temperature limit for stability of the structure and its associated low coercivity was not less than 520 [degrees]C. Index Terms--Crystal structure, Fe-Ti-N film, magnetic properties, thermal stability.

This paper presents a systematic exploration of modifying the electrocaloric effect (ECE) in BaTiO3 ceramics by rare-earth substitution (Ba0.94R0.04TiO3, R = La, Ce, Nd, Sm, Eu, Gd, Dy, Er). All samples exhibit a dense microstructure after sintering in the temperature range of 1350–1450 °C, and they exhibit a high resistivity of ∼1011Ω cm except for Er doped samples due to the amphoteric incorporation of Er. The rare-earth doping changes the lattice symmetry where the tetragonal distortion enhances with the decrease in the rare-earth ionic radius. Accordingly, the ferroelectric and ECE properties are modified and the first-order phase transition is diffused. The Curie temperature and latent heat increases, and the polarization intensity is strengthened with the decrease of the doping ionic radius, while the peak of ECE ΔT widens and shifts to a higher temperature. The samples show a large ECE value of ∼0.35 K m MV−1 over a wide temperature range from room temperature to 140 °C, which provides a series of top-level ECE materials. [ABSTRACT FROM AUTHOR]

200-nm Fe-N thin films deposited on glass substrates by radio-frequency magnetron sputtering were vacuum annealed at 250 [degrees] C-350 [degrees] C under a 12000-A/m magnetic field. Heat treatment was effective in improving the soft magnetic properties of the Fe-N film. When the nitrogen content was in the range of 5-7 atomic %, the thin films consisted of [alpha]' + [alpha]' after heat treatment and had excellent soft magnetic properties: [M.sup.s] = 2.4 T, [H.sub.c] < 80 A/m, [[mirco].sub.r] = 1500 under 2-10 MHz. The properties of the films meet the needs of a write head material used in dual-element giant magnetoresistive/inductive heads. Index Terms--Fe-N film, magnetic properties, magnetron sputtering.

This article compares the effects of Co doping on phase structures and stability of lanthanum strontium titanate (LST) anodes and electrochemical measurements in solid oxide fuel cells (SOFCs) employing H2S-containing H2 as fuel. The Co-doped LST (LSCT) with a perovskite structure was synthesized via a solid state approach, achieving excellent phase purity and refined particle size. The catalytic activity and electrochemical performance are significantly improved by introducing Co. A maximum power density of 300 mW cm−2 was achieved at 900 °C with 5000 ppm H2S–H2 in a fuel cell having a 300 μm thick YSZ electrolyte. Trace amounts of metallic Co nanoparticles with sizes typically no larger than 10 nm in diameter were detected on the LSCT surface after reduction in H2 at 900 °C. The nano-sized Co clusters could reduce the anode polarization resistance, as well as improve the cell performance, compared with undoped LST anodes. The LSCT anode catalyst was electrochemically stable in 5000 ppm H2S–H2 during the test time at high operating temperature. The LSCT anode catalyst also had relatively high redox stability in reversible oxidation–reduction cycles. [ABSTRACT FROM AUTHOR]