High speed low power magnetic devices based on current induced spin-momentum transfer
First Claim
1. A magnetic device comprising:
- a pinned magnetic layer with a magnetization vector with a fixed magnetization direction;
a free magnetic layer with at least one magnetization vector with a changeable magnetization direction;
a first non-magnetic layer spatially separating said free magnetic layer and said pinned magnetic layer;
a read-out magnetic layer with a magnetization vector with a fixed magnetization direction; and
a second non-magnetic layer that spatially separates said free magnetic layer and said read-out magnetic layer such that the mutual magnetic interaction between said free magnetic layer and said read-out magnetic layer is minimized.
2 Assignments
1 Petition
Accused Products
Abstract
The present invention generally relates to the field of magnetic devices for memory cells that can serve as non-volatile memory. More specifically, the present invention describes a high speed and low power method by which a spin polarized electrical current can be used to control and switch the magnetization direction of a magnetic region in such a device. The magnetic device comprises a pinned magnetic layer with a fixed magnetization direction, a free magnetic layer with a free magnetization direction, and a read-out magnetic layer with a fixed magnetization direction. The pinned magnetic layer and the free magnetic layer are separated by a non-magnetic layer, and the free magnetic layer and the read-out magnetic layer are separated by another non-magnetic layer. The magnetization directions of the pinned and free layers generally do not point along the same axis. The non-magnetic layers minimize the magnetic interaction between the magnetic layers. A current is applied to the device to induce a torque that alters the magnetic state of the device so that it can act as a magnetic memory for writing information. The resistance, which depends on the magnetic state of the device, is measured to thereby read out the information stored in the device.
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Citations
35 Claims
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1. A magnetic device comprising:
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a pinned magnetic layer with a magnetization vector with a fixed magnetization direction; a free magnetic layer with at least one magnetization vector with a changeable magnetization direction; a first non-magnetic layer spatially separating said free magnetic layer and said pinned magnetic layer; a read-out magnetic layer with a magnetization vector with a fixed magnetization direction; and a second non-magnetic layer that spatially separates said free magnetic layer and said read-out magnetic layer such that the mutual magnetic interaction between said free magnetic layer and said read-out magnetic layer is minimized. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 33)
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14. A memory system comprising:
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a memory cell comprising; a pinned magnetic layer with a magnetization vector with a fixed magnetization direction; a free magnetic layer with at least one magnetization vector with a changeable magnetization direction; a first non-magnetic layer spatially separating said free magnetic layer and said pinned magnetic layer; a read-out magnetic layer with a magnetization vector with a fixed magnetization direction; and a second non-magnetic layer that spatially separates said free magnetic layer and said read-out magnetic layer such that the mutual magnetic interaction between said free magnetic layer and said read-out magnetic layer is minimized; and an electric current source connected to said pinned magnetic layer and said read-out magnetic layer so that an electric current can traverse said memory cell. - View Dependent Claims (15, 16, 17, 18, 19, 20, 34)
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21. A method of magnetic switching using current-induced spin-momentum transfer, said method comprising the steps of:
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applying an electric current to a magnetic device, wherein said electric current comprises two current pulses wherein one of said two current pulses is a negative current pulse and the other of said two current pulses is a positive current pulse, wherein said current applying step occurs in a sub-nanosecond period of time; and stopping said electric current when a magnetization vector of said magnetic device has rotated 180°
while said electric current is applied.
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22. A method of making a memory cell, said method comprising the steps of:
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forming a first non-magnetic layer on a pinned magnetic layer, said pinned magnetic layer having a magnetization vector with a fixed magnetization direction; forming a free magnetic layer with at least one magnetization vector with a changeable magnetization direction on said first non-magnetic layer; forming a second non-magnetic layer on said free magnetic layer; and forming a read-out magnetic layer with a magnetization vector with a fixed magnetization direction on said second non-magnetic layer. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 35)
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Specification