The exclusive club of magnetic elements officially has a new member-carbon. Using a proton beam and advanced x-ray techniques, SLAC researchers in collaboration with colleagues from LBNL and the University of Leipzig in Germany have finally put to rest doubts about carbon's ability to be made magnetic.

"In the past, some groups thought they had discovered magnetic carbon," said Hendrik Ohldag, the paper's lead author and SSRL staff scientist. "Unfortunately, they realized later that they were misled by small amounts of iron, cobalt or nickel in their samples." In Leipzig, Ohldag's team applied a beam of protons to disrupt and align a portion of the electrons in samples of pure carbon, magnetizing tiny, measurable spots within the carbon. The team then used the x-ray microscope at ALS to obtain images of the magnetized portions-a measurement only possible with a state-of-the-art microscope that uses the brilliant x-ray beams generated when electrons accelerate around the ring of a synchrotron. The x-ray beam also enabled the team to verify beyond doubt that the sample remained free of impurities during the experiments, unlike the case in previous studies.

Harnessing the magnetic properties of carbon could one day revolutionize a range of fields from nanotechnology to electronics. Magnetism, which forms the basis of information storage and processing in computer hard drives, could be employed in novel ways in tomorrow's electronic devices.

The results appeared in the May 4 edition of Physical Review Letters.

To learn more about this research see the full scientific highlight at:
http://www-ssrl.slac.stanford.edu/research/highlights_archive/c_ferromagnetism.html

H. Ohldag, T. Tyliszczak, R. Höhne, D. Spemann, P. Equinazi, M. Ungureanu and T. Butz, p-Electron Ferromagnetism in Metal-Free Carbon Probed by Soft X-ray Dichroism", Phys. Rev. Lett. 98, 187204 (2007)