Magnetoresistance - Fodder for Micro Hard Drives
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Cog·i·ta·tion [koj-i-tey'-shun] – noun: Concerted thought or
reflection; meditation; contemplation.
Kirt [kert] – proper noun: RF Cafe webmaster.
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.