Magnetic tunneling junction structure for magnetic random access memory

Abstract

A magnetic tunneling junction structure for magnetic random access memory is disclosed. A composite structure includes at least a pinning layer, a barrier layer, a ferromagnetic layer and a free layer, and the material of the pinning layer and the free layer are perpendicularly anisotropic ferrimagnetic. As the structures include of several barrier layers, free layers and ferrimagnetic layers, that lower coercivity and high squareness for the hysteresis curves can be obtained, and reduction of the coercivity of the free layer can be achieved.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings,

FIG. 1 illustrates an isometric view of the conventional magnetic tunneling junction structure;

FIG. 2 is a hysteresis curve plot of a magnetic tunneling junction with a conventional structure when a magnetic field between −10,000 and 10,000 Oersted is applied;

FIG. 3 is a hysteresis curve plot of a magnetic tunneling junction with a conventional structure when a magnetic field between −1,000 and 1,000 Oersted is applied;

FIG. 4 illustrates an isometric view of a magnetic tunneling junction structure for a preferred embodiment of the present invention;

FIG. 5 illustrates a hysteresis curve plot of a magnetic tunneling junction with the structure of the present preferred embodiment when a magnetic field between −10,000 and 10,000 Oersted is applied;

FIG. 6 illustrates a hysteresis curve plot of a magnetic tunneling junction with the structure of the present preferred embodiment when a magnetic field between −1,000 and 1,000 Oersted is applied;

FIG. 7 illustrates an isometric view of the magnetic tunneling junction structure for the preferred embodiment of the present invention;

FIG. 8 illustrates a hysteresis curve plot of a magnetic tunneling junction with the structure of the present preferred embodiment when a magnetic field between −10,000 and 10,000 Oersted is applied; and

FIG. 9 illustrates a hysteresis curve plot of a magnetic tunneling junction with the structure of the present preferred embodiment when a magnetic field between −1,000 and 1,000 Oersted.

Claims

1. A structure of a magnetic tunneling junction for magnetic random access memory, comprising: multiple barrier layers, the multiple barrier layers are nonmagnetic and nonconducting films;at least one ferrimagnetic module, the ferrimagnetic module composed of at least two polarized films;a free layer, the free layer is a perpendicular anisotropic ferrimagnetic film, and multiple magnetizations of the free layer are free to rotate with an applied magnetic field; anda pinned layer, the pinned layer is a perpendicular anisotropic ferrimagnetic film.

2. The magnetic tunneling junction structure for magnetic random access memory of claim 1, wherein two polarized films are horizontally polarized films.

3. The magnetic tunneling junction structure for the magnetic random access memory of claim 1, wherein two polarized films are perpendicular polarized films.

4. The magnetic tunneling junction structure for the magnetic random access memory of claim 1, wherein a magnetoresistance of the multiple barrier layers is varied significantly at room temperature.

5. The magnetic tunneling junction structure for magnetic random access memory of claim 1, wherein the multiple barrier layers are between two polarized films of the ferrimagnetic module.

6. The magnetic tunneling junction structure for the magnetic random access memory of claim 1, wherein the material for the multiple barrier layers is non-magnetic films or non-conductive films.

7. The magnetic tunneling junction structure for magnetic random access memory of claim 1, wherein the multiple barrier layers is aluminum oxide, magnesium oxide, or silicon nitride.

8. The magnetic tunneling junction structure for magnetic random access memory of claim 1, wherein thickness of the barrier is ranged from 0.5 nm to 3.5 nm.

9. The magnetic tunneling junction structure for magnetic random access memory of claim 1, wherein the thickness of the ferrimagnetic module is ranged from 1 nm to 4 nm.

10. The magnetic tunneling junction structure for magnetic random access memory of claim 1, wherein material of the free layer is GdFeCo, TbFeCo, DyFeCo or Co/Pt multilayer.

11. The magnetic tunneling junction structure for magnetic random access memory of claim 1, wherein thickness of the free layer is ranged from 35 nm to 60 nm.

12. The magnetic tunneling junction structure for magnetic random access memory of claim 1, wherein material of the pinned layer is GdFeCo, TbFeCo, DyFeCo or Co/Pt multilayer.

13. The magnetic tunneling junction structure for magnetic random access memory of claim 1, wherein thickness of the pinned layer is ranged from 30 nm to 40 nm.

14. The magnetic tunneling junction structure for magnetic random access memory of claim 1, wherein the magnetic tunneling junction structure has multiple electrodes.

15. The magnetic tunneling junction structure for magnetic random access memory of claim 14, wherein material of the electrodes is Pt, Ru, Ta or Ti.

16. The magnetic tunneling junction structure for magnetic random access memory of claim 14, wherein thickness of the electrodes is ranged from 5 nm to 25 nm.