Magnetic Tunnel Junction Based on Ferromagnetic Insulator

A magnetic tunnel junction and insulator technology, applied in the field of non-volatile memory, can solve problems such as large lattice mismatch, interfacial dislocation and potential barrier defects

Active Publication Date: 2019-06-28
BEIHANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the single crystal MgO(001) barrier layer has a large lattice mismatch with commonly used ferromagnetic metal layers such as iron Fe, cobalt iron CoFe, etc., which will cause interface dislocations and barrier defects, which limit the further improvement of the TMR value. improve

Method used

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  • Magnetic Tunnel Junction Based on Ferromagnetic Insulator
  • Magnetic Tunnel Junction Based on Ferromagnetic Insulator
  • Magnetic Tunnel Junction Based on Ferromagnetic Insulator

Examples

Experimental program
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Embodiment 1

[0034] Embodiment 1: as figure 1 , is a structural schematic diagram of a novel MTJ (magnetic tunnel junction) based on a ferromagnetic insulating material as a barrier layer;

[0035]Compared with the traditional MTJ based on the barrier layer of non-magnetic insulator (such as MgO, Al2O3, etc.), the novel MTJ of the present invention uses ferromagnetic insulator as the tunneling barrier layer. The new MTJ core layer structure is composed of ferromagnetic layer I (0-3nm), ferromagnetic insulating layer (0-5nm), and ferromagnetic layer II (0-3nm) from top to bottom; the magnetization direction of each layer can be Parallel to the plane, or all along the vertical direction. The magnetization direction of one layer (reference layer) of the ferromagnetic layer I and ferromagnetic layer II is fixed, and the magnetization direction of the other layer (free layer) can be reversed in a certain way, so that the two layers can be parallel or antiparallel of the two states. Methods t...

Embodiment 2

[0037] Embodiment 2 is a novel MTJ (magnetic tunnel junction) based on a ferromagnetic insulating material as a barrier layer and a non-magnetic spacer layer; the structure consists of a ferromagnetic metal layer 1 (0-3nm) from top to bottom, Nonmagnetic spacer layer (0-3nm), ferromagnetic insulating layer (0-5nm), nonmagnetic spacer layer (0-3nm), ferromagnetic metal layer II (0-3nm) ( Figure 2a ); wherein the ferromagnetic metal layer I, the ferromagnetic metal layer II and the ferromagnetic insulating layer are the same as in Embodiment 1, and a nonmagnetic spacer layer is added between the ferromagnetic metal layer I, the ferromagnetic metal layer II and the ferromagnetic insulating layer , separate them to avoid coupling between two ferromagnetic metal layers in some material systems through a ferromagnetic insulating layer, so that their magnetization directions cannot be separated, and it is impossible to distinguish between parallel and antiparallel magnetization direc...

Embodiment 3

[0039] Embodiment 3 is a novel MTJ (Magnetic Tunnel Junction) based on a ferromagnetic insulating material and adding a heavy metal layer according to the present invention. The structure consists of a ferromagnetic metal layer (0-3nm), a ferromagnetic insulating layer (0-5nm), and a heavy metal layer (0-5nm) from top to bottom ( Figure 3a ); Another structure based on this is to add a non-magnetic spacer layer between the ferromagnetic metal layer and the ferromagnetic insulating layer ( Figure 3b ), to separate them to avoid the coupling effect of the two magnetic layers in some material systems, so that the magnetization directions cannot be separated.

[0040] In this example, the material of the ferromagnetic layer is Co, which is used as a reference layer; the ferromagnetic insulator is YIG, which is used as a barrier layer and also serves as a free layer for inversion; the heavy metal layer is Pt.

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Abstract

The invention relates to a magnetic tunnel junction based on a ferromagnetic insulator, the specific structure is: ferromagnetic metal layer / ferromagnetic insulating layer / ferromagnetic metal layer; the ferromagnetic metal layer is a ferromagnetic metal material such as iron Fe, cobalt Co or nickel One of Ni, or one of ferromagnetic metal alloy materials such as cobalt-iron-CoFe, cobalt-iron-boron CoFeB or nickel-iron NiFe, or a semi-metal or semi-metal alloy material with high spin polarizability such as LaSrMnO 3 , Fe 3 o 4 、Co 2 One of FeAlSi; the material of the ferromagnetic insulating layer includes but is not limited to yttrium iron garnet Y with a higher Curie temperature 3 Fe 5 o 12 , Barium ferrite BaFe 12 o 19 One of. Compared with the current research focus, that is, the magnetic tunnel junction with non-magnetic insulators such as MgO as the barrier layer, the present invention has both ferromagnetic and insulating properties and has been demonstrated in some ferromagnetic insulating materials. Due to the spin filter effect, the magnetic tunnel junction can have better performance, such as higher TMR value.

Description

technical field [0001] The invention relates to a magnetic tunnel junction based on a ferromagnetic insulator, and belongs to the technical field of nonvolatile memory. Background technique [0002] Magnetic tunneling junction (MTJ for short) has important applications in magnetic memory (Magnetic Random Access Memory, MRAM for short), hard disk read head, microwave oscillator, magnetic sensor, etc. Its core is sandwiched by two ferromagnetic layers. A "sandwich" structure composed of an insulating layer, that is, "ferromagnetic metal layer / non-magnetic insulating layer / ferromagnetic metal layer". The magnetization direction of one of the ferromagnetic layers is fixed, called the reference layer or fixed layer; the magnetization direction of the other ferromagnetic layer can be changed to be parallel to the reference layer (Parallel, referred to as P) or antiparallel (Antiparallel). -Parallel, referred to as AP), called the free layer. When the magnetization directions of ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L43/08H01L43/10
CPCH10N50/10H10N50/85
Inventor 赵巍胜刘攀闫韶华
Owner BEIHANG UNIV
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