Magnetic memory with a thermally assisted writing procedure
First Claim
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1. A magnetic memory device of MRAM type with a thermally-assisted writing procedure, the magnetic memory device being formed froma plurality of memory cells, each memory cell comprising:
- a magnetic tunnel junction formed froma magnetic storage layer in which data can be written in a writing process;
a reference layer, having a magnetization being always substantially in the same direction at any time of the writing process;
an insulating layer between the reference layer and the storage layer;
wherein the magnetic tunnel junction further comprises;
a writing layer made of a ferrimagnetic 3d-4f amorphous alloy and comprising;
a net magnetization containing a first magnetization contribution originating from the sub-lattice of 3d transition elements; and
a second magnetization contribution originating from the sub-lattice of 4f rare-earth elements;
wherein the net magnetization of the writing layer is dominated by the second magnetization contribution at a temperature below a compensation temperature TCOMP of the writing layer, and dominated by the first magnetization contribution at a temperature above TCOMP.
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Abstract
A magnetic memory device of MRAM type with a thermally-assisted writing procedure, the magnetic memory device being formed from a plurality of memory cells, each memory cell comprising a magnetic tunnel junction, the magnetic tunnel junction comprising a magnetic storage layer in which data can be written in a writing process; a reference layer, having a magnetization being always substantially in the same direction at any time of the writing process; an insulating layer between the reference layer and the storage layer; wherein the magnetic tunnel junction further comprises a writing layer made of a ferrimagnetic 3d-4f amorphous alloy, and comprising a net magnetization containing a first magnetization contribution originating from the sub-lattice of 3d transition elements and a second magnetization contribution originating from the sub-lattice of 4f rare-earth elements. The magnetic memory device has a low power consumption.
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Citations
15 Claims
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1. A magnetic memory device of MRAM type with a thermally-assisted writing procedure, the magnetic memory device being formed from
a plurality of memory cells, each memory cell comprising: -
a magnetic tunnel junction formed from a magnetic storage layer in which data can be written in a writing process; a reference layer, having a magnetization being always substantially in the same direction at any time of the writing process; an insulating layer between the reference layer and the storage layer; wherein the magnetic tunnel junction further comprises; a writing layer made of a ferrimagnetic 3d-4f amorphous alloy and comprising; a net magnetization containing a first magnetization contribution originating from the sub-lattice of 3d transition elements; and a second magnetization contribution originating from the sub-lattice of 4f rare-earth elements; wherein the net magnetization of the writing layer is dominated by the second magnetization contribution at a temperature below a compensation temperature TCOMP of the writing layer, and dominated by the first magnetization contribution at a temperature above TCOMP. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for writing a magnetic memory device comprising a plurality of memory cells,
each memory cell comprising a magnetic tunnel junction formed from a magnetic storage layer containing a ferromagnetic storage layer having a magnetization that can be reversed during the writing process, a reference layer having a magnetization being always substantially in the same direction during the writing process, and an insulating layer between the reference layer and the storage layer; -
the magnetic tunnel junction further comprising a writing layer made of a ferrimagnetic 3d-4f amorphous alloy comprising a net magnetization containing a first magnetization contribution originating from the sub-lattice of 3d transition elements and a second magnetization contribution originating from the sub-lattice of 4f rare-earth elements; the method comprising; orienting the net magnetization of the writing layer substantially antiparallel to the magnetization of the ferromagnetic storage layer; reversing the magnetization of the first magnetization contribution of the writing layer substantially antiparallel with the magnetization of the ferromagnetic layer; reversing the magnetization of the second magnetization contribution of the writing layer substantially antiparallel with the first magnetization contribution; and reversing the magnetization of the ferromagnetic storage layer substantially antiparallel in respect to the net magnetization of the writing layer. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A method for writing a magnetic memory device comprising
a plurality of memory cells, each memory cell comprising a magnetic tunnel junction formed from a magnetic storage layer containing a ferromagnetic storage layer having a magnetization that can be reversed during the writing process, a reference layer having a magnetization being always substantially in the same direction during the writing process, and an insulating layer between the reference layer and the storage layer; -
the magnetic tunnel junction further comprising a writing layer made of a ferrimagnetic 3d-4f amorphous alloy comprising a net magnetization containing a first magnetization contribution originating from the sub-lattice of 3d transition elements and a second magnetization contribution originating from the sub-lattice of 4f rare-earth elements; the method comprising; an initial step where the net magnetization of the writing layer is oriented antiparallel in respect to the magnetization of the ferromagnetic storage layer due to magnetostatic interactions between the two layers; a second step where the magnetization of the first magnetization contribution of the writing layer is reversed by 180°
compared to its orientation in the initial step;a third step where the magnetization of the second magnetization contribution of the writing layer is reversed by 180°
compared to its direction in the initial state;a fourth step where the magnetization of the ferromagnetic storage layer is reversed by 180°
compared to its direction in the initial state due to magnetostatic interactions between the ferromagnetic storage layer and the writing layer;a final step where the magnetization of the ferromagnetic storage layer and the net magnetization of the writing layer is reversed by 180°
in respect to their respective orientations in the initial step.
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Specification
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Current AssigneeAllegro Microsystems Incorporated (Sanken Electric Company Limited)
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Original AssigneeCrocus Technology S.A. (Sanken Electric Company Limited)
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InventorsPrejbeanu, Ioan Lucian, Nozieres, Jean-Pierre
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Primary Examiner(s)Luu, Pho M
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Application NumberUS12/813,549Publication NumberTime in Patent Office592 DaysField of Search365/158, 365/171, 365/173, 365/189.16US Class Current365/158CPC Class CodesG11C 11/161 details concerning the memo...G11C 11/1675 Writing or programming circ...
