Spin dependent transport devices

Summary form only given. Surveys the status of spin transport materials and device research, and gives the author´s opinion regarding the risks and opportunities which these new materials represent for semiconductor device research. The physical understanding of these new devices is based on the existence of two types of carriers in ferromagnetic conductors, one type with a magnetic moment in the same direction as the magnetization of the material, and the other type with a spin in the opposite direction. A two current model similar to that used for n and p carriers in semiconductors is used to explain operation of the giant magnetoresistance (GMR) and spin dependent tunnelling (SDT) structures. A summary of research results is given for GMR, SDT, and hybrid magnetic/semiconductor devices, along with a summary of proposed applications of these structures. These spin transport structures could provide competition for existing semiconductor technology in the areas of 1) nonvolatile random access memory, 2) magnetic field sensors (e.g. Hall effect sensors), and 3) (in the long term) general active devices. Each of these areas is discussed with an estimate given for the likelihood of success for these new devices.