Applications of spin dependent transport materials

Newly developed materials that exhibit large changes in effective resistanc e with applied fields are being put to practical use. Magnetic multilayers with giant magnetoresistance (GMR) and spin dependent tunnelling (SDT) stru ctures are being used in magnetic field sensors. Spin valves are being sold in read heads for hard drives and galvanic isolators. Both spin valves and SDT structures are being used in non-volatile random access memory develop ment. After a brief introduction to these materials, the development of the ir uses in sensors, read heads, isolators and non-volatile memory are summa rized. GMR magnetic field sensors represent a small, but growing market. SD T sensors have the potential to sense very small fields (to 1 pT). Spin val ve read heads have enabled very high aerial packing densities for hard driv es, up to 24 Gbits per square inch. GMR isolators can be used to duplicate the function of opto-isolators, but at much higher speeds and packing densi ties. Application of these materials to non-volatile random access memory c ould result in speeds and densities of semiconductor memory with the non-vo latility of hard disk drives. Future directions in this field indicate a me rging of semiconductor and these new magnetic materials.