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US5741435A
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Magnetic memory having shape anisotropic magnetic elements
Assignee: Nanosciences Corp
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Filing: 1995-08-08
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Granted: 1998-04-21
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Expires: 2015-08-08
Abstract
Abstract A static magnetic memory includes a layer having a plurality of vertically oriented and shape-anisotropic elongated ferromagnetic particles. A plurality of writing conductors are adjacent the layer, and the conductors selectively apply magnetic fields to selected regions of the layer by directing electrical current to magnetize the particles in an up or down direction. Static reading means detect the direction of magnetization. The particles may include a soft magnet portion and a hard magnet portion. In another preferred embodiment, a material and a method of making same includes providing a matrix full of elongated holes, depositing a first magnetic material having a first coercivity into the holes, and then depositing a second magnetic material having a second coercivity into the holes to form a composite elongated particle in each hole.
Inventors
- 👤 Charles P. Beetz, Jr.
- 👤 John Steinbeck
- 👤 Robert W. Boerstler
- 👤 David R. Winn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:52
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/02; G11C11/14; B; B82; B82Y; B82Y25/00; H; H01; H01F; H01F1/00; H01F1/0036; H01F1/0045; H01F1/0063; H01F1/01; H01F1/03; H01F1/0302; H01F1/0306; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/12; Y10T428/12465; Y10T428/12493; Y10T428/12771; Y10T428/12861; Y10T428/12951
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
50 words
A magnetically anisotropic material comprising a plurality of elongated ferromagnetic particles each having a magnetically soft portion adjacent one end and a magnetically hard portion adjacent the other end, at least the soft portion of each said particle being magnetically shape-anisotropic and a non-magnetic matrix surrounding and supporting said particles.
Claim 2
Dependent Claim
50 words
A magnetically anisotropic material comprising a plurality of elongated ferromagnetic particles each having a magnetically soft portion adjacent one end and a magnetically hard portion adjacent the other end, at least the soft portion of each said particle being magnetically shape-anisotropic and a non-magnetic matrix surrounding and supporting said particles.
Claim 3
Dependent Claim
22 words
A material as claimed in claim 1 wherein each said particle includes a nonmagnetic portion disposed between said hard and soft portions.
Claim 4
Dependent Claim
18 words
A material as claimed in claim 1 wherein the hard portion of each particle is also shape anisotropic.
Claim 5
Dependent Claim
33 words
A material as claimed in claim 3 wherein the particles extend in a vertical direction, substantially parallel to one another, so that each said particle has a top end and a bottom end.
Claim 6
Dependent Claim
25 words
A material as claimed in claim 4 wherein the soft portion of each said particle is disposed adjacent the top end of each said particle.
Claim 7
Dependent Claim
53 words
A material as claimed in claim 5 wherein said particles are vertically aligned with one another so as to form a single layer, the soft portions of said particles being disposed in an upper region of the layer, the hard portions of said particles being disposed in a lower region of said layer.
Claim 8
Dependent Claim
37 words
A material as claimed in claim 3 wherein said hard portions of said particles are composed of one or more metals selected from the group consisting of Fe, Ni, Co, Cr, Pt and oxides and alloys thereof.
Claim 9
Dependent Claim
36 words
A material as claimed in claim 3 wherein said soft portions of said particles are composed of one or more metals selected from the group consisting of Ni, Co, Fe, B and alloys and compounds thereof.
Claim 10
Dependent Claim
33 words
A material as claimed in claim 6 wherein said soft portions of said particles are composed of one or more metals selected from the group consisting of Permalloys, Supermalloys, MuMetal and Iron-Boron alloys.
Claim 11
Dependent Claim
16 words
A material as claimed in claim 9 wherein said soft portions are composed of 78 Permalloy.
Claim 12
Dependent Claim
31 words
A material as claimed in claim 3 wherein said particles have dimensions transverse to their axes of elongation less than the magnetic domain size of the soft portions of the particles.
Claim 13
Dependent Claim
25 words
A material as claimed in claim 11 wherein each said particle has dimensions transverse to its axis of elongation of less than about 0.3 μm.
Claim 14
Dependent Claim
22 words
A material as claimed in claim 12 wherein each said soft portion has an aspect ratio between about 2:1 and about 10:1.
Claim 15
Dependent Claim
29 words
A material as claimed in claim 12 wherein the dimensions of each said particle transverse to its axis of elongation are substantially uniform throughout the length of the particle.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-04-20 | 2001-10-20 | 2002-04-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-04-20 | 2005-10-20 | 2006-04-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-04-20 | 2009-10-20 | 2010-04-21 | $7700.00 | Window Closed / Lapsed |