Magnetoresistance - Fodder for Micro Hard Drives
Researchers at SUNY, Buffalo, NY, have revealed the potential of an effect known as "ballistic magnetoresistance," whereby applying atomic-dimension "nanocontacts" to magnetic media resulted in a 3,000% change in magnetoresistance at low switching fields of a few hundred oersted. This has the potential to increase hard drive storage densities from GBits/in² to TBits/in². Interior magnetic-domain walls measure about 1 nm vs. 100 to 200 nm for a normal conductor. Electrons forced through such a small conduit literally do not have space to bounce around inside the conductor and producing heat. With a nanocontact's 1 nm wide domain walls, electrons stream through, creating a draft-like effect that prompted the label "ballistic." Look for thumbnail-size hard drives in about a decade.