James M Daughton

US Patent:

5969522, Oct 19, 1999

Filed:

Aug 8, 1997

Appl. No.:

8/907561

Inventors:

James M. Daughton - Edina MN
Arthur V. Pohm - Ames IA

International Classification:

G01R 3309
G11B 539

US Classification:

324252

Abstract:

A magnetic field sensing structure for sensing magnetic field changes provided therein having a pair of pole structures with a gap space between them that each include permeable material and end in substantially a common surface. A plurality of field sensing structures is positioned successively in the gap space to be supported between the pole structures with each having an end thereof substantially the common surface. These sensing structures are formed of a plurality of magnetoresistive, anisotropic, ferromagnetic thin-film layers at least two of which are separated from one another by a nonmagnetic, electrically conductive layer positioned between them. They are electrically connected to one another adjacent the common surface, and may be electrically connected to one of the pole structures.

US Patent:

6349053, Feb 19, 2002

Filed:

Jun 26, 2001

Appl. No.:

09/891619

Inventors:

James M. Daughton - Edina MN
Brenda A. Everitt - Minneapolis MN
Arthur V. Pohm - Ames IA

Assignee:

NVE Corporation - Eden Prairie MN

International Classification:

G11C 1115

US Classification:

365145, 365173

Abstract:

A digital data memory having a bit structure in a memory cell based on a dielectric intermediate separating material with two major surfaces having thereon an anisotropic ferromagnetic thin-film of differing thicknesses. These bit structures are fabricated within structural extent limits to operate satisfactorily, and are fabricated as series connected members of storage line structures. A corresponding conductive word line structure adjacent corresponding ones of these memory cells is used for selecting or operating them, or both, in data storage and retrieval operations.

US Patent:

6404191, Jun 11, 2002

Filed:

Mar 22, 2001

Appl. No.:

09/814637

Inventors:

James M. Daughton - Eden Prairie MN
Arthur V. Pohm - Ames IA

Assignee:

NVE Corporation - Eden Prairie MN

International Classification:

G11B 5127

US Classification:

324252, 32420721, 360103

Abstract:

A plurality of magnetic field sensing structures in a monolithic integrated circuit chip structure to provide output signals at outputs thereof of magnetic field changes provided therein from corresponding sources having poled pair structures with a gap space between them with adjacent ones of the magnetic field sensing structures that are interconnected with a circuit formed in the monolithic integrated circuit chip such as an amplifier. The paired pole structures may intersect a surface of the chip perpendicular to the major surfaces thereof or in one of, or a surface parallel to, the major surfaces thereof. A magnetic field generating structure may also be included in the chip.

US Patent:

6429640, Aug 6, 2002

Filed:

Aug 21, 2000

Appl. No.:

09/643902

Inventors:

James Daughton - Eden Prairie MN
John Stokes - Rochester MN

Assignee:

The United States of America as represented by the Secretary of the Air Force - Washington DC

International Classification:

G01R 3300

US Classification:

324117R, 324252, 32420721

Abstract:

A configuration where a wide range of current can be sensed accurately in spite of using a magnetic material with non-linearities and limited hysteresis. This configuration includes: a strip line current carrier, an IC chip containing a GMR sensor element, an integrated drive coil, like an isoloop. Field produced by current in the strip line is detected by the sensor. Feedback field is produced by current in an on-chip coil to counteract spurious fields from the strip line.

US Patent:

6462541, Oct 8, 2002

Filed:

Nov 12, 1999

Appl. No.:

09/439892

Inventors:

Dexin Wang - Eden Prairie MN
Mark C. Tondra - Minneapolis MN
James M. Daughton - Eden Prairie MN

Assignee:

NVE Corporation - Eden Prairie MN

International Classification:

G01R 3302

US Classification:

324252, 360324

Abstract:

A ferromagnetic thin-film based sensing arrangement having a plurality of magnetic field sensors on a substrate each having an intermediate layer of a nonmagnetic material with two major surfaces on opposite sides thereof with one of a pair of magnetically permeable films each of a magnetoresistive, anisotropic ferromagnetic material correspondingly positioned thereon with first and second oriented sensors therein respectively having a selected and a reversing magnetization orientation structure provided with one of said pair of permeable films thereof for orienting its magnetization in a selected direction absent an externally applied magnetic field in at least partly opposing directions. Alternatively, these magnetizations of the films can be oriented in the same direction but with the other film member of the pair provided adjacent a coupling layer that antiferromagnetically couples thereto a further ferromagnetic layer on an opposite side thereof of a lesser thickness for one sensor and a greater thickness for the other. Such a sensing arrangement can be formed by providing a succession of material layers on a substrate with one or more coupling layers for antiferromagnetically coupling ferromagnetic layers on opposite sides thereof including a permeable film. Selective removal of the succession follows to provide unequal numbers of coupling layers for the two kinds of sensors or unequal thicknesses of corresponding ferromagnetic layers corresponding to the coupling layer and the providing of a pinning layer for both kinds of sensors which are thereafter separated by further material removal.

US Patent:

6535416, Mar 18, 2003

Filed:

Apr 23, 2001

Appl. No.:

09/673827

Inventors:

James M. Daughton - Eden Prairie MN
Arthur V. Pohm - Ames IA

Assignee:

NVE Corporation - Eden Prairie MN

International Classification:

G11C 1122

US Classification:

365145, 365148, 365173

Abstract:

A ferromagnetic thin-film based digital memory (FIG. ) having in a bit structure ( ) a coupled moment material film ( ) in which magnetic moments of adjacent atoms, ions or molecules are coupled to one another to maintain some alignment thereof below a critical temperature above which such alignment is not maintained, and also having a plurality of word line structures ( ) each located across from the coupled moment material film ( ) in a corresponding one of the bit structures ( ). The bit structures ( ) are sufficiently thermally isolated to allow currents in the adjacent word lines ( ) and/or the bit structure ( ) to heat the bit structure ( ) to approach the critical temperature which may be supplied coincidently and then reduced to cool the bit structure ( ) while supplying a magnetic field during the cooling.

US Patent:

6538921, Mar 25, 2003

Filed:

Aug 14, 2001

Appl. No.:

09/929435

Inventors:

James M. Daughton - Eden Prairie MN
Arthur V. Pohm - Ames IA

Assignee:

NVE Corporation - Eden Prairie MN

International Classification:

G11C 1114

US Classification:

365171, 365170

Abstract:

A ferromagnetic thin-film based digital memory having a plurality of bit structures interconnected with manipulation circuitry having a plurality of transistors so that each bit structure has transistors electrically coupled thereto that selectively substantially prevents current in at least one direction along a current path through that bit structure and permits selecting a direction of current flow through the bit structure if current is permitted to be established therein. A bit structure has a nonmagnetic intermediate layer with two major surfaces on opposite sides thereof and a memory film of an anisotropic ferromagnetic material on each of the intermediate layer major surfaces with an electrically insulative intermediate layer is provided on the memory film on which a magnetization reference layer is provided having a fixed magnetization direction.

US Patent:

6713195, Mar 30, 2004

Filed:

Jan 7, 2002

Appl. No.:

10/041910

Inventors:

Dexin Wang - Eden Prairie MN
Zhenghong Qian - Eden Prairie MN
James M. Daughton - Eden Prairie MN
Robert T. Fayfield - St. Louis Park MN

Assignee:

NVE Corporation - Eden Prairie MN

International Classification:

G11B 566

US Classification:

428692, 428332, 428333, 428668, 428678, 428469, 428698

Abstract:

A ferromagnetic thin-film based magnetoresistive device with a first ferromagnetic material based film having electrically conductive, ferromagnetic material nanogranules embedded in an intergranular material of a smaller electrical conductivity first nonmagnetic. The device may have an intermediate layer adjacent the first ferromagnetic material based film and a second film is on the other side of the intermediate layer of a substantially ferromagnetic material. The first film is less than 1. 0 m thick.