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Synthesis of ferromagnetic carbon nanometer tube

A technology of carbon nanotubes and synthesis methods, applied in nanotechnology, nanotechnology, nanostructure manufacturing, etc.

Inactive Publication Date: 2006-02-22
NANJING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

So far, some organic ferromagnets with high Tc have been found, such as: highly oriented cracked graphite, graphite in meteorites, graphite irradiated by protons, C 60 Oxidation products, amorphous carbon, and carbon foams, among others, these findings challenge the understanding of ferromagnetism in carbon-based materials

Method used

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  • Synthesis of ferromagnetic carbon nanometer tube
  • Synthesis of ferromagnetic carbon nanometer tube
  • Synthesis of ferromagnetic carbon nanometer tube

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Put a porcelain boat with 1 g of Zn powder into a quartz tube as a catalyst, and take a clean porcelain boat as a substrate, with a distance of 2 cm between the two. Enter Ar gas (60sccm) at 10℃min -1 Start to heat up at a rate of 460℃, and pass H 2 (20sccm), enter C at 500℃ 2 H 2 (20sccm); continue to heat up to 800℃, and keep at this temperature for 30min; finally at 8℃min -1 The rate drops to room temperature.

[0029] Collect the product on the substrate and divide it into two parts, one part is treated with ultra-pure concentrated HCl and the other part is not treated with HCl. The ICP method was used to determine the content of metal impurities in the two samples, and their magnetic properties were tested on the SQUID instrument. Observe its morphology and structure with transmission electron microscope ( figure 1 ). M-T curve( Figure 6a ) Shows the existence of two long-range ordered ferromagnetic phases (Tc is about 500K and above 800K respectively); M-H curve ( F...

Embodiment 2

[0031] Put a porcelain boat with 1g of Zn powder into a quartz tube as a catalyst; take a clean porcelain boat as a substrate, and the two are separated by 2 cm. Enter Ar gas (60sccm) at 10℃min -1 The rate of heating is increased, and C is passed to 500℃ 2 H 2 (20sccm); continue to heat up to 800℃, and keep it at this temperature for 30min; stop passing acetylene, then use 8℃min -1 The rate drops to room temperature.

[0032] Collect the product on the substrate, observe its morphology and structure with SEM and TEM, then wrap it with 99.99% aluminum foil and test its magnetic properties with SQUID. TEM reveals figure 1 Similar morphology and structure, M-H curve shows the existence of hysteresis loop, Ms is 0.22emug -1 (300K), Hc is 145Oe (300K).

Embodiment 3

[0034] Put a porcelain boat with 1g of Zn powder into a quartz tube as a catalyst; another clean quartz plate is taken as a substrate, and the distance between the two is 4cm. Then let in Ar gas (60sccm) at 14℃min -1 Heat up at a rate of 460℃, pass H 2 (20sccm), switch the carrier gas flow to CH at 500℃ 3 CH 2 OH vapor saturator, bubbling through CH 3 CH 2 OH and Zn vapor enter the reaction zone after mixing, continue to heat up to 850 ℃, and keep at this temperature for 30 minutes, stop passing CH 3 CH 2 OH steam, then at 10℃min -1 The rate drops to room temperature.

[0035] The product on the substrate was collected and treated with ultra-pure concentrated HCl, and the yield was significantly reduced compared to Example 1. TEM reveals figure 1 Similar morphology and structure, using VSM to test its magnetic properties, M-H curve shows the existence of hysteresis, Ms is 0.385emug -1 (300K), Hc is 167Oe (300K).

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Abstract

Synthesis of ferromagnetic carbon nanometer tube is disclosed. It includes 1) putting porcelain boat, quartz or single-crystal silicon slice into quartz tube as substrate and putting another porcelain boat with zinc powder into quartz tube as catalytic source; 2) inducing insert gas, inducing hydrogen at 450-550deg.C, inducing carbon source at 500-600deg.C, heating to 750-1000deg.C, and keeping temperature for 15-50 mins; 3) shutting carbon source, shutting hydrogen and insert gas until to room temperature, and collecting products on substrate. It achieves good stability and repeatability.

Description

1. Technical Field [0001] The invention relates to a method for synthesizing ferromagnetic carbon nanotubes under the action of a non-magnetic metal catalyst. 2. Background technology [0002] Scientists generally believe that only materials composed of elements containing 3d and 4f electrons can have a long-range ordered ferromagnetic phase. There are questions about whether pure organic materials can become ferromagnetics, but because organic ferromagnets have outstanding advantages such as light weight Advantages, therefore, efforts to find organic ferromagnets have not stopped. Since 1990, some organic ferromagnets have been discovered one after another, but due to weak magnetism and low ferromagnetic transition temperature (Tc), they did not attract enough attention from the academic community until Makarova and his collaborators discovered the rhombohedral structure in 2001. C 60 Polymer has ferromagnetism and Tc is as high as 500K, which has triggered a new round of resear...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B31/00B82B3/00
Inventor 徐正韩敏
Owner NANJING UNIV