Response of an extraordinary magnetoresistance read head to a magnetic bit

It has been proposed earlier that the extraordinary magnetoresistance (EMR) observed at room temperature in nonmagnetic semiconducting materials containing metallic inhomogeneities can be used in suitably constructed read heads for magnetic storage devices. Here, we show that such read heads are much simpler in design, and allow for higher sensitivity than is observed using magnetic layered structures that employ the phenomenon of giant magnetoresistance. We calculate, with no adjustable material parameters, the room-temperature response of an EMR read-head design, using finite element analysis, as a function of the position of the magnetic bit relative to the read head. The scaling property of the EMR bodes well for increasing the storage density to 1 Tbit/in.(2) in the near future. (C) 2003 American Institute of Physics.