Giant junction magnetoresistance effect in ferromagnet/semiconductor heterostructures

The effect of magnetic field on the electrical transport across the ferromagnet/semiconductor heterostructures has been investigated. The heterostructures were fabricated by growing ferromagnetic layer of cobalt on silicon and germanium substrates. Studies were made for both etched and oxide (alumina) coated surfaces. Some of the heterostructures show very good rectifying property at all temperatures and spin-valve like characteristics at low temperatures. Positive giant junction magnetoresistance is observed in the heterostructures below a critical temperature. This resulted to a drastic reduction of the forward current in the devices on application of a small magnetic field. The observed giant magnetoresistance is unique, and the interface of the heterostructures is inferred to be strongly influencing the transport characteristics of the device. (C) 2013 AIP Publishing LLC.