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Graphite made magnetic By irradiating ultrapure graphite with protons, researchers at the University of Leipzig, in Germany, report that they were able to prepare a pure carbon magnet that is lightweight and metal-free and can retain its magnetism even at room temperature [Phys. Rev. Lett., 91, 227201 (2003)]. Organic samples previously reported to be magnetic were held at temperatures close to absolute zero. Other reports of carbon-based magnets that are stable at room temperature have been received with skepticism because of weak magnetic properties, metallic impurities, and low reproducibility. Using ultrapure graphite and irradiation allowed the Leipzig group, led by physics professor Pablo D. Esquinazi, to circumvent the possibility of contamination with magnetic metallic impurities. Esquinazi suspects that the magnetic effect arises when the protons form C–H bonds that distort the graphite lattice in a way that generates the magnetic properties. He speculates that this technique could be used to make the smallest magnet possible by implanting hydrogen at the edges of carbon nanotubes |
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