Patent Number: 6,480,365

Title: Spin valve transistor using a magnetic tunnel junction

Abstract: A spin valve transistor sensor is provided having a emitter element, acollector element and a common base element. The negatively biased emitterelement injects a spin polarized hot electron current into the baseelement by tunneling from a ferromagnetic pinned layer to a ferromagneticfree layer through a first tunnel barrier layer. The positively biasedcollector element, comprising a second tunnel barrier layer and anonmagnetic metal layer, collects the fraction of the hot electron currentthat passes through the base element and over the barrier height of thesecond tunnel barrier layer. The hot electron current is strongly spinpolarized and due to the GMR effect in the magnetic tunnel junctionelement, the magnitude of the base-collector current is strongly dependenton external magnetic (signal) fields. A process is provided forfabrication of a spin valve transistor sensor suitable for high densitymagnetic recording applications.

Inventors: Gill; Hardayal (Harry) Singh (Portola Valley, CA), Monsma; Douwe Johannes (Palo Alto, CA)


International Classification: G11B 5/39 (20060101); G11B 5/33 (20060101); G11B 005/127 ()

Expiration Date: 11/12014