Patent ID: 7969692

Claim:
A magnetic reading head comprising: a conductive layer; a first element unit, which is formed by superposing a ferromagnetic layer on the conductive layer with an insulating barrier layer interposed in between, and in which the conductive layer and the ferromagnetic layer constitute part of a current-supplying circuit; and a second element unit, which is formed by superposing a ferromagnetic layer on the conductive layer with an insulating barrier layer interposed in between, and in which the conductive layer and the ferromagnetic layer constitute part of a voltage-measurement circuit, wherein spin-polarization at an interface of a junction between the ferromagnetic layer and the insulating barrier layer of the second element unit is greater than spin-polarization at an interface of a junction between the ferromagnetic layer and the insulating barrier layer of the first element unit, wherein a film for fixing magnetization of the ferromagnetic layer of the first element unit is formed on a surface of the ferromagnetic layer, which surface is located on a side opposite a surface which is in contact with the insulating barrier layer, wherein the insulating barrier layer of the second element unit is crystalline, and wherein a principal crystal structure of the ferromagnetic layer of the second element unit, in volumetric terms, is in any one of a face-centered cubic lattice, an amorphous structure and a mixed state of the face-centered cubic lattice and the amorphous state.