Ultrahigh efficient spin orbit torque magnetization switching in fully sputtered topological insulator and ferromagnet multilayers.

Spin orbit torque (SOT) magnetization switching of ferromagnets with large perpendicular magnetic anisotropy has a great potential for the next generation non-volatile magnetoresistive random-access memory (MRAM). It requires a high performance pure spin current source with a large spin Hall angle and high electrical conductivity, which can be fabricated by a mass production technique. In this work, we demonstrate ultrahigh efficient and robust SOT magnetization switching in fully sputtered BiSb topological insulator and perpendicularly magnetized Co/Pt multilayers. Despite fabricated by the magnetron sputtering instead of the laboratory molecular beam epitaxy, the topological insulator layer, BiSb, shows a large spin Hall angle of θSH = 10.7 and high electrical conductivity of σ = 1.5 × 105 Ω-1 m-1. Our results demonstrate the feasibility of BiSb topological insulator for implementation of ultralow power SOT-MRAM and other SOT-based spintronic devices.

Efficient spin current source using a half-Heusler alloy topological semimetal with back end of line compatibility.

Topological materials, such as topological insulators (TIs), have great potential for ultralow power spintronic devices, thanks to their giant spin Hall effect. However, the giant spin Hall angle (θSH > 1) is limited to a few chalcogenide TIs with toxic elements and low melting points, making them challenging for device integration during the silicon Back-End-of-Line (BEOL) process. Here, we show that by using a half-Heusler alloy topological semi-metal (HHA-TSM), YPtBi, it is possible to achieve both a giant θSH up to 4.1 and a high thermal budget up to 600 °C. We demonstrate magnetization switching of a CoPt thin film using the giant spin Hall effect of YPtBi by current densities lower than those of heavy metals by one order of magnitude. Since HHA-TSM includes a group of three-element topological materials with great flexibility, our work opens the door to the third-generation spin Hall materials with both high θSH and high compatibility with the BEOL process that would be easily adopted by the industry.

[Three-dimensional vertically aligned CNTs coated by Ag nanoparticles for surface-enhanced Raman scattering].

In order to make surface-enhanced Raman scattering (SERS) substrates contained more "hot spots" in a three-dimensional (3D) focal volume, and can be adsorbed more probe molecules and metal nanoparticles, to obtain stronger Raman spectral signal, a new structure based on vertically aligned carbon nanotubes (CNTs) coated by Ag nanoparticles for surface Raman enhancement is presented. The vertically aligned CNTs are synthesized by chemical vapor deposition (CVD). A silver film is first deposited on the vertically aligned CNTs by magnetron sputtering. The samples are then annealed at different temperature to cause the different size silver nanoparticles to coat on the surface and sidewalls of vertically aligned CNTs. The result of scanning electron microscopy(SEM) shows that Ag nanoparticles are attached onto the sidewalls and tips of the vertically aligned CNTs, as the annealing temperature is different , pitch size, morphology and space between the silver nanoparticles is vary. Rhodamine 6G is served as the probe analyte. Raman spectrum measurement indicates that: the higher the concentration of R6G, the stronger the Raman intensity, but R6G concentration increase with the enhanced Raman intensity varies nonlinearly; when annealing temperature is 450 °C, the average size of silver nanoparticles is about 100 to 120 nm, while annealing temperature is 400 °C, the average size is about 70 nm, and the Raman intensity of 450 °C is superior to the annealing temperature that of 400 °C and 350 °C.

Three-dimensional multi-walled carbon nanotube arrays coated by gold-sol as a surface-enhanced Raman scattering substrate.

We demonstrated a three-dimensional (3D) surface-enhanced Raman scattering (SERS) substrate consisting of large area carbon nanotube (CNT) arrays coated by gold-sol nanoparticles. A low-cost, simple process is used to prepare Au-decorated 3D CNT arrays. The SERS enhancement from the 3D CNT arrays, and two-dimensional (2D) CNT films substrates coated by different size gold-sol nanoparticles, was experimentally verified with Rhodamine 6G as the probe analyte. The experiments showed that the 3D CNT arrays substrate has a higher Raman enhancement compared with 2D CNT arrays substrate and planar glass substrate, due to the large specific surface area of CNT arrays and more gold nanoparticles on the CNT arrays sidewalls, which contribute the electromagnetic field and Raman intensity. Meanwhile, the 3D structure could enhance the excitation light trapping in CNT arrays, consequently increasing the light interaction with Au nanoparticles.

Protective effect of Weikang decoction and partial ingredients on model rat with gastric mucosa ulcer.

AIM: To investigate the protective mechanisms of Weikang (WK) decoction on gastric mucosae. METHODS: Ninety rats were randomly divided into nine groups of 10 each, namely group, model group, group with large WK dosage, group with medium WK dosage, group with small WK dosage, group with herbs of jianpiyiqi (strengthening the spleen and replenishing qi), group with herbs of yangxuehuoxue (invigorating the circulation of and nourishing the blood), group with herbs of qingrejiedu (clearing away the heat-evils and toxic materials), group with colloidal bismuth pectin (CBP) capsules. According to the method adopted by Yang Xuesong, except normal control group, chronic gastric ulcer was induced with 100% acetic acid. On the sixth day after moldmaking, WK decoction was administered, respectively at doses of 20, 10 and 5 g/kg to rats of the WK groups, or the groups with herbs of jianpiyiqi, yangxuehuoxue and qingrejiedu, 10 mL/kg was separately administered to each group every day. For the group with CBP capsules, medicine was dissolved with water and doses 15 times of human therapeutic dose were administered (10 mL/kg solution containing 0.35% CBP). Rats of other groups were fed with physiological saline (10 mL/kg every day). Administration lasted for 16 d. Rats were killed on d 22 after mold making to observe changes of gastric mucosa. The mucus thickness of gastric mucosa surface was measured. Levels of epidermal growth factor (EGF) in gastric juice, nitric oxide (NO) in gastric tissue, endothelin (ET) in plasma, superoxide dismutase (SOD) in plasma, malondialdehyde (MDA) in plasma and prostaglandin I(2) (PGI(2)) were examined. RESULTS: Compared with control group, ulceration was found in gastric mucosa of model group rats. The mucus thickness of gastric mucosa surface, the levels of EGF, NO, 6-K-PGF(1)alpha and SOD decreased significantly in the model group (EGF: 0.818+/-0.18 vs 2.168+/-0.375, NO: 0.213+/-0.049 vs 0.601+/-0.081, 6-K-PGF(1)alpha: 59.7+/-6.3 vs 96.6+/-8.30, SOD: 128.6+/-15.0 vs 196.6+/-35.3, P<0.01), the levels of ET (179.96+/-37.40 vs 46.64+/-21.20, P<0.01) and MDA (48.2+/-4.5 vs 15.7+/-4.8, P<0.01) increased. Compared with model group, the thickness of regenerative mucosa increased, glandular arrangement was in order, and cystic dilative glands decreased, while the mucus thickness of gastric mucosa surface increased (20 g/kg WK: 51.3+/-2.9 vs 23.2+/-8.4, 10 g/kg WK: 43.3+/-2.9 vs 23.2+/-8.4, 5 g/kg WK: 36.1+/-7.2 vs 23.2+/-8.4, jianpiyiqi: 35.4+/-5.6 vs 23.2+/-8.4, yangxuehuoxue: 33.1+/-8.9 vs 23.2+/-8.4, qingrejiedu: 31.0+/-8.0 vs 23.2+/-8.4 and CBP: 38.2+/-3.5 vs 23.2+/-8.4, P<0.05-0.01). The levels of EGF (20 g/kg WK: 1.364+/-0.12 vs 0.818+/-0.18, 10 g/kg WK: 1.359+/-0.24 vs 0.818+/-0.18, 5 g/kg WK: 1.245+/-0.31 vs 0.818+/-0.18, jianpiyiqi: 1.025+/- 0.45 vs 0.818+/-0.18, yangxuehuoxue: 1.03+/-0.29 vs 0.818+/-0.18, qingrejiedu: 1.02+/-0.47 vs 0.818+/-0.18 and CBP: 1.237+/-0.20 vs 0.818+/-0.18, P<0.05-0.01), NO (20 g/kg WK: 0.480+/-0.026 vs 0.213+/-0.049, 10 g/kg WK: 0.390+/-0.055 vs 0.213+/-0.049, 5 g/kg WK: 0.394+/-0.026 vs 0.213+/-0.049, jianpiyiqi: 0.393+/-0.123 vs 0.213+/-0.049, yangxuehuoxue: 0.463+/-0.077 vs 0.213+/-0.049, qingrejiedu: 0.382+/-0.082 vs 0.213+/-0.049 and CBP: 0.395+/-0.053 vs 0.213+/-0.049, P<0.05-0.01), 6-K-PGF(1)alpha (20 g/kg WK: 86.8+/-7.6 vs 59.7+/-6.3, 10 g/kg WK: 77.9+/-7.0 vs 59.7+/-6.3, 5 g/kg WK: 70.0+/-5.4 vs 59.7+/-6.3, jianpiyiqi: 73.5+/-12.2 vs 59.7+/-6.3, yangxuehuoxue: 65.1+/-5.3 vs 59.7+/-6.3, qingrejiedu: 76.9+/-14.6 vs 59.7+/-6.3, and CBP: 93.7+/-10.7 vs 59.7+/-6.3, P<0.05-0.01) and SOD (20 g/kg WK: 186.4+/-19.9 vs 128.6+/-15.0, 10 g/kg WK: 168.2+/-21.7 vs 128.6+/-15.0, 5 g/kg WK: 155.6+/-21.6 vs 128.6+/-15.0, jianpiyiqi: 168.0+/-85.3 vs 128.6+/-15.0, yangxuehuoxue: 165.0+/-34.0 vs 128.6+/-15.0, qingrejiedu: 168.2+/-24.9 vs 128.6+/-15.0, and CBP: 156.3+/-18.1 vs 128.6+/-15.0, P<0.05-0.01) significantly increased. The levels of ET (20 g/kg WK: 81.30+/-17.20 vs 179.96+/-37.40, 10 g/kg WK: 83.40+/-25.90 vs 179.96+/-37.40, 5 g/kg WK: 93.87+/-20.70 vs 179.96+/-37.40, jianpiyiqi: 130.67+/-43.66 vs 179.96+/-37.40, yangxuehuoxue: 115.88+/-34.09 vs 179.96+/-37.40, qingrejiedu: 108.22+/-36.97 vs 179.96+/-37.40, and CBP: 91.96+/-19.0 vs 179.96+/-37.40, P<0.01) and MDA (20 g/kg WK: 21.6+/-7.4 vs 48.2+/-4.5, 10 g/kg WK: 32.2+/-7.3 vs 48.2+/-4.5, 5 g/kg WK: 34.2+/-6.2 vs 48.2+/-4.5, jianpiyiqi: 34.9+/-13.8 vs 48.2+/-4.5, yangxuehuoxue: 35.5+/-16.7 vs 48.2+/-4.5, qingrejiedu: 42.2+/-17.6 vs 48.2+/-4.5, and CBP: 30.1+/-6.1 vs 48.2+/-4.5, P<0.05-0.01) obviously decreased. The 20 g/kg WK group was better than 10 g/kg (the mucus thickness: 51.3+/-2.9 vs 43.3+/-2.9, NO: 0.480+/-0.026 vs 0.390+/-0.055, SOD: 186.4+/-19.9 vs 168.2+/-21.7, P<0.01) and 5 g/kg (the mucus thickness: 51.3+/-2.9 vs 36.1+/-7.2, NO: 0.480+/-0.026 vs 0.394+/-0.026, SOD: 186.4+/-19.9 vs 155.6+/-21.6, P<0.01) groups and CBP group (the mucus thickness: 51.3+/-2.9 vs 38.2+/-3.5, NO: 0.480+/-0.026 vs 0.395+/-0.053, SOD: 186.4+/-19.9 vs 156.3+/-18.1, P<0.01) in the mucus thickness, NO and SOD levels and better than 10 g/kg (86.8+/-7.6 vs 77.9+/-7.0, P<0.05) and 5 g/kg (86.8+/-7.6 vs 70.0+/-5.4, P<0.05) groups in 6-K-PGF(1)alpha level, 10 g/kg WK group was better than 5 g/kg WK (the mucus thickness: 43.3+/-2.9 vs 36.1+/-7.2, P<0.01, SOD: 168.2+/-21.7 vs 155.6+/-21.6, P<0.05) and CBP groups (the mucus thickness: 43.3+/-2.9 vs 38.2+/-3.5, P<0.01, SOD: 168.2+/-21.7 vs 156.3+/-18.1, P<0.05) in the mucus thickness and SOD level. In compound group, jianpiyiqi group, yangxuehuoxue group, qingrejiedu group, the level of ET was decreased, NO contents were increased in gastric tissue of ulcers in rats. CONCLUSION: WK decoction and separated recipes have significantly protective effect on ethanol-induced gastric mucosal injury. They can increase the content of EGF in gastric juice, PGI(2) SOD in plasma and NO in gastric tissues, thicken the mucus on the gastric mucosa, and decrease the impairing factor MDA, ET in plasma.