A magnetic force microscope using CoFe-coated carbon nanotube probes

Ferromagnetic-film-coated carbon nanotube (CNT) probes were employed in a magnetic force microscope (MFM) observation. We succeeded in making a uniform ferromagnetic film on the CNT probes by improving the coating process and selecting materials. The performance of the CoFe-coated CNT probe was evaluated in ultra-high-density perpendicular magnetic storage media with densities from 600 to 1100 k flux changes per inch (FCI). The magnetic domain structure of the magnetic storage media was clearly observed up to 1100 kFCI. The ultimate lateral resolution of the newly developed MFM probes is down to about 10 nm, which exceeds the bit length of a magnetic recording with a density of Tbit inch(-2).