IP Library Granted Patent US 7,050,329
Granted Patent B2
US 7,050,329 · App. 10/962,252 · Granted May 23, 2006

Magnetic spin based memory with inductive write lines

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Quick Facts
Patent No.
US 7,050,329
App. No.
10/962,252
Granted
May 23, 2006
Kind
B2
Abstract

A new nonvolatile hybrid memory cell is provided. The cell is comprised of a magnetic spin storage element which is written using inductive write lines. The magnetic spin storage element is an electron spin-based memory element situated on a silicon based substrate and includes a first ferromagnetic layer with a changeable magnetization state, and a second ferromagnetic layer with a non-changeable magnetization state. A current of spin polarized electrons has a magnitude which can be varied so that a data value can be stored in the memory element by varying a relative orientation of the two ferromagnetic layers using a magnetic field imposed by the inductive write lines.

Claims (40)

1. A hybrid magnetoelectronic spin-based memory cell comprising:

a memory element configured to transport a current of spin polarized electrons including:

i) a first ferromagnetic layer with a first magnetization state;

ii) a second ferromagnetic layer with a second magnetization state;

wherein a data value stored in the hybrid magnetoelectronic spin-based memory cell can be determined by measuring a magnitude of said current of spin polarized electrons, which current of spin polarized electrons varies in accordance with a relationship between said first magnetization state and said second magnetization state;

iii) a pair of write lines inductively coupled to said memory element, which pair of write lines carry a pair of respective current write signals adapted to change said first magnetization state and alter said data value.

2. The hybrid magnetoelectronic spin-based memory cell of claim 1 , wherein said pair of write lines are configured so that that the presence of a current write signal on only one of said pair write lines generates a magnetic field that is insufficient to alter said first magnetization state.

3. The hybrid magnetoelectronic spin-based memory cell of claim 1 , wherein said memory element is situated above a semiconductor based select transistor.

4. The hybrid magnetoelectronic spin-based memory cell of claim 1 further including a low transmission barrier located between said first ferromagnetic layer and said second ferromagnetic layer.

5. The hybrid magnetoelectronic spin-based memory cell of claim 3 wherein the semiconductor based transistor is a field effect transistor (FET).

6. The hybrid magnetoelectronic spin-based memory cell of claim 3 wherein the semiconductor based transistor isolation element is a bipolar junction transistor (BJT).

7. The hybrid magnetoelectronic spin-based memory cell of claim 1 , further including a read line coupled to read said data value from said memory element, which read line is separate from said pair of write lines.

8. The hybrid magnetoelectronic spin-based memory cell of claim 1 , wherein said pair of write lines uses a single polarity current pulse.

9. The hybrid magnetoelectronic spin-based memory cell of claim 1 , wherein said pair of write lines partially overlap.

10. The hybrid magnetoelectronic spin-based memory cell of claim 1 , wherein said memory element is a spin transistor.

11. The hybrid magnetoelectronic spin-based memory cell of claim 1 , wherein said first ferromagnetic layer and said second ferromagnetic layer each include at least two separate layers.

12. The hybrid magnetoelectronic spin-based memory cell of claim 1 , wherein both a current pulse and a voltage pulse are used to read data stored by said electron spin-based memory element.

13. A hybrid magnetoelectronic spin-based memory cell comprising:

a memory element situated over a silicon based substrate and which is configured to transport a current of spin polarized electrons, including:

i) a first ferromagnetic layer with a first changeable magnetization state comprising iron, permalloy and/or cobalt;

ii) a second ferromagnetic layer with a second non-changeable magnetization state also comprising iron, permalloy and/or cobalt;

wherein a magnitude of a spin polarized current passing through both said first ferromagnetic layer a second ferromagnetic layer can be varied to represent a data value in said memory cell having at least two logic levels;

iii) a pair of write lines inductively coupled to said memory element, which pair of write lines carry a pair of respective current write signals adapted to change said first changeable magnetization state and alter said data value.

14. The hybrid magnetoelectronic spin-based memory cell of claim 13 , wherein said memory element is stacked on top of a second memory element.

15. The hybrid magnetoelectronic spin-based memory cell of claim 14 , wherein said memory element and said second memory element share a semiconductor based memory cell selector.

16. The hybrid magnetoelectronic spin-based memory cell of claim 13 , wherein said memory element is a three terminal, current biased device.

17. The hybrid magnetoelectronic spin-based memory cell of claim 16 , including a conductive paramagnetic base layer situated between said first ferromagnetic layer and said second ferromagnetic layer, and which is adapted to create a nonequilibrium population of spin polarized electrons and an equivalent nonequilibrium magnetization M.

18. The hybrid magnetoelectronic spin-based memory cell of claim 17 , wherein said nonequilibrium magnetization M in said paramagnetic conductive paramagnetic base layer base generates an electric field at an interface with said first ferromagnetic layer.

19. The hybrid magnetoelectronic spin-based memory cell of claim 13 , wherein said spin polarized current has a magnitude that varies based on whether said first changeable magnetization state and said second non-changeable magnetization state are parallel or antiparallel.

20. A hybrid magnetoelectronic spin-based memory cell comprising:

a memory element situated over a silicon based substrate and which is configured to transport a current of spin polarized electrons, including:

i) a first ferromagnetic layer with a changeable magnetization state comprising iron, permalloy and/or cobalt;

ii) a second ferromagnetic layer with a non-changeable magnetization state also comprising iron, permalloy and/or cobalt;

iii) a low transmission barrier interface between said first ferromagnetic layer and said second ferromagnetic layer;

wherein said current of spin polarized electrons passes through said first ferromagnetic layer, said low transmission barrier interface, and said second ferromagnetic layer, and has a magnitude which can be varied by changing a relative orientation of said changeable magnetization state and said non-changeable magnetization state so as to store a data value in said memory element;

iv) a pair of write lines inductively coupled to said memory element, which pair of write lines carry a pair of respective current write signals adapted to change said changeable magnetization state and alter said data value.

21. The hybrid magnetoelectronic spin-based memory cell of claim 20 , wherein an output voltage is provided at a terminal coupled to said first ferromagnetic layer for reading said data value.

22. The hybrid magnetoelectronic spin-based memory cell of claim 20 wherein said second ferromagnetic layer is a bilayer including both a first ferromagnetic conductor layer and a second nonmagnetic conductor layer, which second nonmagnetic conductor layer is used to control a magnetic behavior of said first ferromagnetic conductor layer.

23. The hybrid magnetoelectronic spin-based memory cell of claim 20 , further including a read line coupled to read data from said memory element, which read line is separate from said pair of write lines.

24. The hybrid magnetoelectronic spin-based memory cell of claim 20 , wherein said low transmission barrier interface includes Niobium.

Assignments (4)
RELEASE OF SECURITY INTEREST Recorded Jul 23, 2025
From: THE BANK OF NOVA SCOTIA
To: SEAGATE TECHNOLOGY PUBLIC LIMITED COMPANY; SEAGATE TECHNOLOGY; SEAGATE TECHNOLOGY HDD HOLDINGS; I365 INC.; SEAGATE TECHNOLOGY LLC; SEAGATE TECHNOLOGY INTERNATIONAL; SEAGATE HDD CAYMAN; SEAGATE TECHNOLOGY (US) HOLDINGS, INC.
Reel/Frame 072193/0001 →
TERMINATION AND RELEASE OF SECURITY INTEREST IN PATENT RIGHTS Recorded Jul 19, 2013
From: WELLS FARGO BANK, NATIONAL ASSOCIATION, AS COLLATERAL AGENT AND SECOND PRIORITY REPRESENTATIVE
To: SEAGATE TECHNOLOGY LLC; EVAULT INC. (F/K/A I365 INC.); SEAGATE TECHNOLOGY INTERNATIONAL; SEAGATE TECHNOLOGY US HOLDINGS, INC.
Reel/Frame 030833/0001 →
TERMINATION AND RELEASE OF SECURITY INTEREST IN PATENT RIGHTS Recorded Jul 19, 2013
From: THE BANK OF NOVA SCOTIA, AS ADMINISTRATIVE AGENT
To: SEAGATE TECHNOLOGY INTERNATIONAL
Reel/Frame 030836/0078 →
SECURITY AGREEMENT Recorded Mar 24, 2011
From: SEAGATE TECHNOLOGY INTERNATIONAL
To: THE BANK OF NOVA SCOTIA, AS ADMINISTRATIVE AGENT
Reel/Frame 026010/0871 →