Patent ID: 6934133

Claim:
A three terminal magnetic head comprising: a magnetic semiconductor; a magnetic multilayer film having a first ferromagnetic layer formed on said magnetic semiconductor, a second ferromagnetic layer formed on said first ferromagnetic layer, and a first non-magnetic layer formed between said first and second ferromagnetic layers; a tunnel magnetoresistive film having said second ferromagnetic layer, a third ferromagnetic layer formed on said second ferromagnetic layer, and a first tunnel barrier layer formed between said second and third ferromagnetic layers; a first electrode connected electrically to the magnetic semiconductor; a second electrode connected electrically to one of said first ferromagnetic layer, said first non-magnetic layer, and said second ferromagnetic layer; and a third electrode connected electrically to said third ferromagnetic layer, wherein a current is controlled to flow between said first and third electrodes to allow a tunnel current to flow into said tunnel magnetoresistive film through said magnetic semiconductor and said magnetic multilayer film, and a direction of magnetization of said second ferromagnetic layer changes upon application of an external magnetic field and a resistance change caused by the changed direction of magnetization being detected by said second and third electrodes.