In proposed laboratory-on-a-chip systems, magnetic biological marker nano-beads adhere to an immobilization surface when a targeted biological agent is present. Spintronic biosensors detect magnetic perturbations from the nano-beads to detect and quantify the presence of very low levels of biological or chemical materials.
Physicists at the University of California, San Diego have proposed a design for a semiconductor computer circuit based on the spin of electrons. They say the device would be more scalable and have greater computational capacity than conventional silicon circuits.
The âspintronicââor spin-based electronicâdevice, described this week in the journal Nature, would extend the scope of conventional electronics by encoding information with the magneticâor spinâstate of electrons, in addition to the charge of the electrons. The researchers used a novel geometry to overcome the weakness of the magnetic signal, the current limitation to developing spintronics in silicon semiconductors.
The proposed spintronic circuit is an interconnected series of logic gates. Each logic gate consists of five magnetic contacts lying on top of a semiconductor layer. The magnetic state of each of these contacts, determined by the electronsâ spins, corresponds to the â0â and â1â in each bit of information. The logic operation is performed by moving electrons between four of the magnetic contacts and the semiconductor. The result of the operation is read by the fifth magnetic contact.
The proposed device has not yet been made, but according to the researchers it should be feasible with currently available technology.