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Nickel Sensors Could Raise Hard Disk Capacity
Makarand writes "Tiny filaments of nickel, thinner than a wavelength of visible light, acting as magnetic
sensors may expand the storage capacity of hard disks many times. Although, technologies
exist to increase hard disk capacity, reading data bits reliably from such disks has proven
difficult because as data bits become smaller their magnetic fields are weaker and difficult
to pick up. Nickel filaments are capable of picking up of these weak magnetic fields
using a phenomenon called "ballistic magnetoresistance" which is not completely understood.
As the sensors are only a few atoms wide the electrons travel along a straight line
in the conductor greatly enhancing the binary signal picked up from the data bits.
These sensors could also be used to detect biomolecules in low concentrations."
That depends on how many spins an atom can have at once:) Welcome to the world of quatum mechanics.
Visual light takes up just a small segment of the electromagnetic spectrum. There are shorter wavelengths they can use to detect it.