Patents by Inventor Philip R Hammar

Philip R Hammar has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Magnetoresistive spin-injection diode
    Patent number: 6297987
    Abstract: A spin injected diode suitable for nonvolatile memory applications is made of a semiconducting channel capable of carrying current, a single ferromagnetic layer, and a barrier layer between the semiconducting channel and the ferromagnetic layer to protect the integrity of the semiconducting layer and to inhibit interdiffusion of the ferromagnetic material and the semiconductor. During diode readout the output modulation of the diode can be sensed either as the interface resistance between the semiconducting channel and the ferromagnetic layer, or as the output voltage between the semiconducting channel and the ferromagnetic layer when flowing current through the channel and not through the interface. Two of these spin injected diodes can be combined to form a spin injected field effect transistor. This transistor has a first ferromagnetic layer having a first coercivity and a second ferromagnetic layer having a second coercivity smaller than the first coercivity which are spaced apart.
    Type: Grant
    Filed: September 30, 1999
    Date of Patent: October 2, 2001
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Mark B. Johnson, Brian Bennett, Philip R Hammar