Zhanghao Pan

Giant low-field magnetostriction of epoxy/TbxDy1-x(Fe0.8Co0.2)2 composites (0.20 ≤ x ≤ 0.40)

Spin configuration, magnetocrystalline anisotropy compensation, and magnetostriction of TbxDy1−x(Fe0.8Co0.2)2 (0.20 ≤ x ≤ 0.40) compounds have been investigated. Experimental evidence for the anisotropy compensation has been observed directly by performing x-ray diffraction on magnetic-field aligned powders and by evaluating the Mossbauer spectra. The easy magnetization direction (EMD) at room temperature rotates from the ⟨100⟩ (x ≤ 0.27) to the ⟨111⟩ axis (x ≥ 0.32), subjected to the anisotropy compensation between Tb3+ and Dy3+ ions. The strong grain-⟨111⟩-oriented pseudo-1–3 epoxy/composite has been fabricated by curing under a moderate magnetic field. A giant low-field magnetostriction, longitudinal λ|| and linear anisotropic λa (=λ|| − λ⊥) up to 550 and 760 ppm at 3 kOe, respectively, is obtained for Tb0.32Dy0.68(Fe0.8Co0.2)2 composite, which can be attributed to anisotropy compensation, a large magnetostriction coefficients λ111, EMD lying along ⟨111⟩ direction, the strong ⟨111⟩-textured orientation...

1.5-14 μm midinfrared supercontinuum generation in a low-loss Te-based chalcogenide step-index fiber.

We have experimentally demonstrated midinfrared (MIR) supercontinuum (SC) generation in a low-loss Te-based chalcogenide (ChG) step-index fiber. The fiber, fabricated by an isolated extrusion method, has an optical loss of 2-3 dB/m at 6.2-10.3 μm and 3.2 dB/m at 10.6 μm, the lowest value reported for any Te-based ChG step-index fiber. A MIR SC spectrum (∼1.5 to 14 μm) is generated from the 23-cm fiber pumped by a 4.5 μm laser (∼150  fs, 1 kHz). To the best of our knowledge, this is the first SC experimental demonstration in Te-based ChG fiber and the broadest MIR SC generation pumped in the normal dispersion regime in the optical fibers.

Novel Ge–Ga–Te–CsBr glass system with ultrahigh resolvability of halide

CO2 molecule, one of the main molecules to create new life, should be probed accurately to detect the existence of life in exoplanets. The primary signature of CO2 molecule is approximately 15 μm, and traditional S- and Se-based glass fibers are unsuitable. Thus, Te-based glass is the only ideal candidate glass for far-infrared detection. In this study, a new kind of Te-based chalcohalide glass system was discovered with relatively stable and large optical band gap. A traditional melt-quenching method was adopted to prepare a series of (Ge15Ga10Te75)100-x (CsBr)x chalcogenide glass samples. Experiment results indicate that the glass-forming ability and thermal properties of glass samples were improved when CsBr was added in the host of Ge-Ga-Te glass. Ge-Ga-Te glass could remarkably dissolve CsBr content as much as 85 at.%, which is the highest halide content in all reports for Te-based chalcohalide glasses. Moreover, ΔT values of these glass samples were all above 100 °C. The glass sample (Ge15Ga10Te75)65 (CsBr)35 with ΔT of 119 °C was the largest, which was 7 °C larger than that of Ge15Ga10Te75 host glass. The infrared transmission spectra of these glasses show that the far-infrared cut-off wavelengths of (Ge15Ga10Te75)100-x (CsBr)x chalcogenide glasses were all beyond 25 μm. In conclusion, (Ge15Ga10Te75)100-x (CsBr)x chalcogenide glasses are potential materials for far-infrared optical application.

Enhanced magnetostrictive effect in epoxy-bonded TbxDy0.9-xNd0.1(Fe0.8Co0.2)(1.93) pseudo 1-3 particulate composites

The spin configuration and spontaneous magnetostriction λ111 of TbxDy0.9−xNd0.1(Fe0.8Co0.2)1.93 (0.20 ≤ x ≤ 0.60) alloys have been investigated. The easy magnetization direction (EMD) at room temperature was observed towards the 〈111〉 axis when 0.40 ≤ x ≤ 0.60, accompanied by a rhombohedral distortion with large spontaneous magnetostriction coefficients λ111, which increases from 1640 ppm for x = 0.40 to 1900 ppm for x = 0.60. The strong 〈111〉-oriented pseudo 1–3 particulate composite was fabricated by embedding and aligning particles in a passive epoxy matrix under an applied magnetic field. An enhanced magnetostrictive effect, the large low-field magnetostriction, λa, as high as 480 ppm at 3 kOe, was obtained for the sample of x = 0.40, in an excess of 75% of its polycrystalline alloy although it only contains 27 vol. % alloy particles. This enhanced effect can be attributed to its low magnetic anisotropy, anisotropic magnetostrictive nature (e.g., λ111 ≠ λ100, 〈111〉EMD), chain structure, and the 〈111〉-...

Microstructure and magnetostrictive properties of epoxy-bonded Tb1-xNdx(Fe0.8Co0.2)1.93 (0.20 ≤ x ≤ 0.75) composites

An epoxy-resin bonding route was used to produce composite rods of the highly magnetostrictive alloys Tb1-xNdx(Fe0.8Co0.2)1.93 (0.20 ≤ x ≤ 0.75). The structure, spin configuration, magnetostriction and particle size are investigated by means of X-ray diffraction (XRD), a standard strain technique and scanning electron microscope (SEM). The epoxy-bonded 0–3 type and pseudo 1–3 type composites are successfully fabricated, respectively. XRD analysis shows that the easy magnetization direction (EMD) for the alloy of x = 0.20 lies along 〈111〉 axis. The magnetic curing field makes the particles align as a particulate chain and also causes the particles rotating along its EMD direction. The pseudo 1–3 type epoxy-bonded composite has a larger magnetostriction than that of the 0–3 type composite, which can be attributed to the larger magnetostriction coefficient λ111, EMD lying along 〈111〉 direction, the 〈111〉-textured orientation and the chain structure. A large saturation magnetostriction (λ0S ~ 570 ppm) is achieved for the 1–3 type epoxy/Tb0.35Nd0.65(Fe0.8Co0.2)1.93 composite (about 150–250 μm, 10 kOe), which approaches 70% of its monolithic alloy. Furthermore, it only contains 27 vol.% alloy particles in the insulating epoxy matrix and performs a low magnetic anisotropy, which could make it technologically interesting for the field of Nd-containing magnetostrictive materials.