US 2004/0170055 A1Published application

Magnetostatically coupled magnetic elements utilizing spin transfer and an MRAM device using the magnetic element

AssigneeGrandis, Inc.

InventorsFrank Albert, Yiming Huai, Paul P. Nguyen

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Abstract

A method and system for providing a magnetic element and a corresponding memory are disclosed. In one aspect, the method and system include providing a dual spin tunnel/valve structure and at least one spin valve. The dual spin tunnel/valve structure includes a nonmagnetic spacer layer between a pinned layer and a free layer, another pinned layer and a barrier layer between the free layer and the other pinned layer. The free layers of the dual spin tunnel/valve structure and the spin valve are magnetostatically coupled. In one embodiment a separation layer resides between the dual spin tunnel/valve structure and the spin valve. In another aspect, the method and system include providing two dual spin valves, a spin tunneling junction there between and, in one embodiment, the separation layer. In both aspects, the magnetic element is configured to write to the free layers using spin transfer when a write current is passed through the magnetic element.

Claims40

Dependent claims

A magnetic element comprising:

a dual spin tunnel/valve structure including a first pinned layer, a barrier layer, a first free layer, a first nonmagnetic spacer layer, and a second pinned layer, the first pinned layer being ferromagnetic and having a first pinned layer magnetization, the first pinned layer magnetization being pinned in a first direction, the barrier layer being an insulator and having a thickness that allows tunneling through the barrier layer, the barrier layer being disposed between the first pinned layer and the first free layer, the first free layer being ferromagnetic and having a first free layer magnetization, the first nonmagnetic spacer layer being conductive and disposed between the second pinned layer and the first free layer, the second pinned layer being ferromagnetic and having a second pinned layer magnetization pinned in a second direction;
a spin valve structure having a third pinned layer, a second nonmagnetic spacer layer and a second free layer, the third pinned layer being ferromagnetic and having a third pinned layer magnetization, the third pinned layer magnetization being pinned in a third direction, the second free layer being ferromagnetic and having a second free layer magnetization, the second nonmagnetic spacer layer being conductive and residing between the second free layer and the second pinned layer, the first free layer and the second free layer being disposed such that the first free layer and the second free layer are magnetostatically coupled;
wherein the magnetic element is configured to allow the first and/or second free layer magnetization to change direction due to spin transfer when a write current is passed through the magnetic element.

A magnetic element comprising:

a spin tunneling junction having a first pinned layer, a barrier layer, and a first free layer, the barrier layer residing between the first pinned layer and the first free layer, the first pinned layer being ferromagnetic and having a first pinned layer magnetization pinned in a first direction, the first free layer being ferromagnetic and having a first free layer magnetization, the barrier layer being an insulator and having a first thickness that allow tunneling through the barrier layer;
a first dual spin valve having a second pinned layer, a first nonmagnetic spacer layer, a second free layer, a second nonmagnetic spacer layer and a third pinned layer, the second pinned layer residing between the second free layer and the first free layer, the first nonmagnetic spacer layer being conductive and residing between the second pinned layer and the second free layer, the second free layer residing between the second pinned layer and the third pinned layer, the second nonmagnetic spacer layer being conductive and residing between the second free layer and the third pinned layer, the second pinned layer being ferromagnetic and having a second pinned layer magnetization pinned in a second direction, the third pinned layer being ferromagnetic and having a third pinned layer magnetization pinned in a third direction, the second free layer being ferromagnetic and having a second free layer magnetization, the first free layer and the second free layer being magnetostatically coupled;
a second dual spin valve having a fourth pinned layer, a third nonmagnetic spacer layer, a third free layer, a fourth nonmagnetic spacer layer and a fifth pinned layer, the fourth pinned layer residing between the first free layer and the third free layer, the third nonmagnetic spacer layer being conductive and residing between the fourth pinned layer and the third free layer, the fourth nonmagnetic spacer layer being conductive and residing between the third free layer and the fifth pinned layer, the fourth pinned layer being ferromagnetic and having a fourth pinned layer magnetization pinned in a fourth direction, the fifth pinned layer being ferromagnetic and having a fifth pinned layer magnetization pinned in a fifth direction, the third free layer being ferromagnetic and having a third free layer magnetization, the first free layer and the third free layer being magnetostatically coupled;
wherein the magnetic element is configured to allow the second free layer magnetization and the third free layer magnetization to change direction due to spin transfer when a write current is passed through the magnetic element.

1 more element

A magnetic memory device comprising:

a plurality of magnetic cells including a plurality of magnetic elements, each of the plurality of magnetic elements including a dual spin tunnel/valve structure and a spin valve structure, the dual spin tunnel/valve structure including a first pinned layer, a barrier layer, a first free layer, a first nonmagnetic spacer layer, and a second pinned layer, the first pinned layer being ferromagnetic and having a first pinned layer magnetization, the first pinned layer magnetization being pinned in a first direction, the barrier layer being an insulator and having a thickness that allows tunneling through the barrier layer, the barrier layer being disposed between the first pinned layer and the first free layer, the first free layer being ferromagnetic and having a first free layer magnetization, the first nonmagnetic spacer layer being conductive and disposed between the second pinned layer and the first free layer, the second pinned layer being ferromagnetic and having a second pinned layer magnetization pinned in a second direction, the spin valve structure having a third pinned layer, a second nonmagnetic spacer layer and a second free layer, the third pinned layer being ferromagnetic and having a third pinned layer magnetization, the third pinned layer magnetization being pinned in a third direction, the second free layer being ferromagnetic and having a second free layer magnetization, the second nonmagnetic spacer layer being conductive and residing between the second free layer and the second pinned layer, the first free layer and the second free layer being disposed such that the first free layer and the second free layer are magnetostatically coupled, the magnetic element is configured to allow the first and/or second free layer magnetization to change direction due to spin transfer when a write current passed through the magnetic element;
a plurality of row lines coupled to the plurality of magnetic cells;
and
a plurality of column lines coupled with the plurality of cells, the plurality of row lines and the plurality of column lines for selecting a portion of the plurality of magnetic cells for reading and writing.

1 more element

A magnetic memory device comprising:

a plurality of magnetic cells including a plurality of magnetic elements, each of the plurality of magnetic elements including a spin tunneling junction, a first dual spin valve and a second dual spin valve, the spin tunneling junction having a first pinned layer, a barrier layer, and a first free layer, the barrier layer residing between the first pinned layer and the first free layer, the first pinned layer being ferromagnetic and having a first pinned layer magnetization pinned in a first direction, the first free layer being ferromagnetic and having a first free layer magnetization, the barrier layer being an insulator and having a first thickness that allow tunneling through the barrier layer, the first dual spin valve having a second pinned layer, a first nonmagnetic spacer layer, a second free layer, a second nonmagnetic spacer layer and a third pinned layer, the second pinned layer residing between the second free layer and the first free layer, the first nonmagnetic spacer layer being conductive and residing between the second pinned layer and the second free layer, the second free layer residing between the second pinned layer and the third pinned layer, the second nonmagnetic spacer layer being conductive and residing between the second free layer and the third pinned layer, the second pinned layer being ferromagnetic and having a second pinned layer magnetization pinned in a second direction, the third pinned layer being ferromagnetic and having a third pinned layer magnetization pinned in a third direction, the second free layer being ferromagnetic and having a second free layer magnetization, the first free layer and the second free layer being magnetostatically coupled, the second dual spin valve having a fourth pinned layer, a third nonmagnetic spacer layer, a third free layer, a fourth nonmagnetic spacer layer and a fifth pinned layer, the fourth pinned layer residing between the first free layer and the third free layer, the third nonmagnetic spacer layer being conductive and residing between the fourth pinned layer and the third free layer, the fourth nonmagnetic spacer layer being conductive and residing between the third free layer and the fifth pinned layer, the fourth pinned layer being ferromagnetic and having a fourth pinned layer magnetization pinned in a fourth direction, the fifth pinned layer being ferromagnetic and having a fifth pinned layer magnetization pinned in a fifth direction, the third free layer being ferromagnetic and having a third free layer magnetization, the first free layer and the third free layer being magnetostatically coupled, wherein the magnetic element is configured to allow the second free layer magnetization and the third free layer magnetization to change direction due to spin transfer when a write current is passed through the magnetic element;
a plurality of row lines coupled to the plurality of magnetic cells;
and
a plurality of column lines coupled with the plurality of cells, the plurality of row lines and the plurality of column lines for selecting a portion of the plurality of magnetic cells for reading and writing.

1 more element

A method for utilizing a magnetic memory comprising the steps of:

(a) in a write mode, writing to a first portion of a plurality of magnetic cells by driving a write current in a CPP configuration through the first portion of a plurality of magnetic elements, each of the magnetic elements including a dual spin tunnel/valve structure and a spin valve structure, the dual spin tunnel/valve structure including a first pinned layer, a barrier layer, a first free layer, a first nonmagnetic spacer layer, and a second pinned layer, the first pinned layer being ferromagnetic and having a first pinned layer magnetization, the first pinned layer magnetization being pinned in a first direction, the first nonmagnetic spacer layer being conductive and disposed between the first pinned layer and the first free layer, the first free layer being ferromagnetic and having a first free layer magnetization, the barrier layer being an insulator and having a thickness that allows tunneling through the barrier layer, the barrier layer being disposed between the second pinned layer and the first free layer, the second pinned layer being ferromagnetic and having a second pinned layer magnetization pinned in a second direction, the spin valve structure having a third pinned layer, a second nonmagnetic spacer layer and a second free layer, the third pinned layer being ferromagnetic and having a third pinned layer magnetization, the third pinned layer magnetization being pinned in a third direction, the second free layer being ferromagnetic and having a second free layer magnetization, the second nonmagnetic spacer layer being conductive and residing between the second free layer and the second pinned layer, the first free layer and the second free layer being disposed such that the first free layer and the second free layer are magnetostatically coupled, the magnetic element is configured to allow the first and/or second free layer magnetization to change direction due to spin transfer when a write current is passed through the magnetic element;
and
(b) in a read mode, reading a signal from a second portion of the plurality of magnetic cells.

A method for utilizing a magnetic memory comprising the steps of:

(a) in a write mode, writing to a first portion of a plurality of magnetic cells by driving a write current in a CPP configuration through the first portion of a plurality of magnetic elements, each of the magnetic elements including a plurality of magnetic cells including a plurality of magnetic elements, each of the plurality of magnetic elements including a spin tunneling junction, a first dual spin valve and a second dual spin valve, the spin tunneling junction having a first pinned layer, a barrier layer, and a first free layer, the barrier layer residing between the first pinned layer and the first free layer, the first pinned layer being ferromagnetic and having a first pinned layer magnetization pinned in a first direction, the second pinned layer being ferromagnetic and having a second pinned layer magnetization pinned in a second direction, the first free layer being ferromagnetic and having a first free layer magnetization, the barrier layer being an insulator and having a first thickness that allow tunneling through the barrier layer, the first dual spin valve having a second pinned layer, a first nonmagnetic spacer layer, a second free layer, a second nonmagnetic spacer layer and a third pinned layer, the second pinned layer residing between the second free layer and the first free layer, the first nonmagnetic spacer layer being conductive and residing between the second pinned layer and the second free layer, the second free layer residing between the second pinned layer and the third pinned layer, the second nonmagnetic spacer layer being conductive and residing between the second free layer and the third pinned layer, the second pinned layer being ferromagnetic and having a second pinned layer magnetization pinned in a second direction, the third pinned layer being ferromagnetic and having a third pinned layer magnetization pinned in a third direction, the second free layer being ferromagnetic and having a second free layer magnetization, the first free layer and the second free layer being magnetostatically coupled, the second dual spin valve having a fourth pinned layer, a third nonmagnetic spacer layer, a third free layer, a fourth nonmagnetic spacer layer and a fifth pinned layer, the fourth pinned layer residing between the first free layer and the third free layer, the third nonmagnetic spacer layer being conductive and residing between the fourth pinned layer and the third free layer, the fourth nonmagnetic spacer layer being conductive and residing between the third free layer and the fifth pinned layer, the fourth pinned layer being ferromagnetic and having a fourth pinned layer magnetization pinned in a fourth direction, the fifth pinned layer being ferromagnetic and having a fifth pinned layer magnetization pinned in a fifth direction, the third free layer being ferromagnetic and having a third free layer magnetization, the first free layer and the third free layer being magnetostatically coupled, wherein the magnetic element is configured to allow the second free layer magnetization and the third free layer magnetization to change direction due to spin transfer when a write current is passed through the magnetic element;
and
(b) in a read mode, reading a signal from a second portion of the plurality of cells.

A method for providing magnetic element comprising the steps of:

(a) providing a dual spin tunnel/valve structure including a first pinned layer, a barrier layer, a first free layer, a first nonmagnetic spacer layer and a second pinned layer, the first pinned layer being ferromagnetic and having a first pinned layer magnetization, the first pinned layer magnetization being pinned in a first direction, the barrier layer being an insulator and having a thickness that allows tunneling through the barrier layer, the barrier layer being disposed between the first pinned layer and the first free layer, the first free layer being ferromagnetic and having a first free layer magnetization, the first nonmagnetic spacer layer being conductive and disposed between the second pinned layer and the first free layer, the second pinned layer being ferromagnetic and having a second pinned layer magnetization pinned in a second direction;
and
(b) providing a spin valve structure having a third pinned layer, a second nonmagnetic spacer layer and a second free layer, the third pinned layer being ferromagnetic and having a third pinned layer magnetization, the third pinned layer magnetization being pinned in a third direction, the second free layer being ferromagnetic and having a second free layer magnetization, the second nonmagnetic spacer layer being conductive and residing between the second free layer and the second pinned layer, the first free layer and the second free layer being disposed such that the first free layer and the second free layer are magnetostatically coupled;
wherein the magnetic element is configured to allow the first and/or second free layer magnetization to change direction due to spin transfer when a write current is passed through the magnetic element.

1 more element

A method for providing a magnetic element comprising the steps of:

(a) providing a spin tunneling junction having a first pinned layer, a barrier layer, and a first free layer, the barrier layer residing between the first pinned layer and the first free layer, the first pinned layer being ferromagnetic and having a first pinned layer magnetization pinned in a first direction, the second pinned layer being ferromagnetic and having a second pinned layer magnetization pinned in a second direction, the first free layer being ferromagnetic and having a first free layer magnetization, the barrier layer being an insulator and having a first thickness that allow tunneling through the barrier layer;
(b) providing a first dual spin valve having a second pinned layer, a first nonmagnetic spacer layer, a second free layer, a second nonmagnetic spacer layer and a third pinned layer, the second pinned layer residing between the second free layer and the first free layer, the first nonmagnetic spacer layer being conductive and residing between the second pinned layer and the second free layer, the second free layer residing between the second pinned layer and the third pinned layer, the second nonmagnetic spacer layer being conductive and residing between the second free layer and the third pinned layer, the second pinned layer being ferromagnetic and having a second pinned layer magnetization pinned in a second direction, the third pinned layer being ferromagnetic and having a third pinned layer magnetization pinned in a third direction, the second free layer being ferromagnetic and having a second free layer magnetization, the first free layer and the second free layer being magnetostatically coupled;
(c) providing a second dual spin valve having a fourth pinned layer, a third nonmagnetic spacer layer, a third free layer, a fourth nonmagnetic spacer layer and a fifth pinned layer, the fourth pinned layer residing between the first free layer and the third free layer, the third nonmagnetic spacer layer being conductive and residing between the fourth pinned layer and the third free layer, the fourth nonmagnetic spacer layer being conductive and residing between the third free layer and the fifth pinned layer, the fourth pinned layer being ferromagnetic and having a fourth pinned layer magnetization pinned in a fourth direction, the fifth pinned layer being ferromagnetic and having a fifth pinned layer magnetization pinned in a fifth direction, the third free layer being ferromagnetic and having a third free layer magnetization, the first free layer and the third free layer being magnetostatically coupled, wherein the magnetic element is configured to allow the second free layer magnetization to change direction due to spin transfer when a write current is passed through the magnetic element.

Dependencies are inferred from the claim text.