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Generation of nonvolatile skyrmions in multilayer films

A non-volatile, multi-layer film technology, applied in the field of non-volatile skyrmion generation, can solve the problem of non-zero field stability

Active Publication Date: 2019-12-06
INST OF PHYSICS - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

from figure 2 It can be concluded that after the external magnetic field is withdrawn, the formed skyrmions return to strip magnetic domains. Although skyrmions can be formed at room temperature in the Pt / Co / Ta multilayer film material system, a continuous magnetic field is required. to make it stable at room temperature, so it does not have zero-field stability and is a volatile skyrmion

Method used

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  • Generation of nonvolatile skyrmions in multilayer films
  • Generation of nonvolatile skyrmions in multilayer films
  • Generation of nonvolatile skyrmions in multilayer films

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Step 1): Using magnetron sputtering to prepare a platinum / cobalt / tantalum (Pt / Co / Ta) sandwich structure multilayer film on a silicon nitride substrate with a window, mount the substrate on an electric field bar and insert it into a transmission electron microscope observe. The thickness of Pt in the Pt / Co / Ta multilayer film is 5nm, the thickness of Co is 2nm, the thickness of Ta is 5nm, and the thickness of the silicon nitride substrate window is 10nm.

[0029] Step 2): Directly use the objective lens current in the transmission electron microscope to generate the required magnetic field, and apply a magnetic field with a magnetic induction intensity of 30mT perpendicular to the film surface of the Pt / Co / Ta multilayer film, wherein the magnetic field of 30mT is not enough to make the strip magnetic domains into skyrmions;

[0030] Step 3): directly using the keithley ammeter in the transmission electron microscope to apply an in-plane current to the Pt / Co / Ta multilayer...

Embodiment 2

[0035] It is basically the same as Example 1, except that a magnetic field of 40 mT is applied in step 2) (this magnetic field is also insufficient to transform the stripe magnetic domains in the multilayer Pt / Co / Ta into skyrmions). Figure 4 is the magnetic domain structure diagram of skyrmions obtained according to the above generation method after the external field is removed. from Figure 4 It can be seen that the density of the formed skyrmions is significantly higher than figure 1 The density of skyrmions is shown, and the skyrmions formed by the above generation method can still be stored stably after the withdrawal of the current and the applied magnetic field, and have non-volatile zero-field stability.

Embodiment 3

[0037] It is basically the same as Example 1, except that a magnetic field of 50 mT is applied in step 2) (this magnetic field is also insufficient to convert the stripe magnetic domains in the multilayer Pt / Co / Ta into skyrmions). Figure 5 is the magnetic domain structure diagram of skyrmions obtained according to the above generation method after the external field is removed. from Figure 5 It can be seen that the density of the formed skyrmions is significantly higher than figure 1 The density of skyrmions is shown, and the skyrmions formed by the above generation method can still be stored stably after the withdrawal of the current and the applied magnetic field, and have non-volatile zero-field stability.

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Abstract

The invention provides a method for generating a nonvolatile skyrmion in a multilayer film. The multilayer film includes a first heavy metal layer, a ferromagnetic layer, and a second heavy metal layer sequentially stacked; the first heavy metal layer and the second heavy metal layer refer to two different kinds of metal films, and induction is conducted on an interface between the first heavy metal layer and the ferromagnetic layer and an interface between the second heavy metal layer and the ferromagnetic layer, and thus DM interaction is generated. The generation method includes the following steps that 1, a predetermined magnetic field is applied to the multilayer film, the intensity of a magnetic field is not enough, so that a strip-type magnetic domain in the multilayer film is converted into the skyrmion, and the direction of the magnetic field is not parallel to the film surface of the multilayer film; 2, predetermined current is applied to the multilayer film, so that the strip-type magnetic domain is transformed into the skyrmion. According to the generation method, the high-density skyrmion stably existing at the room temperature in a zero field is formed.

Description

technical field [0001] The invention relates to a method for generating skyrmions, in particular to a method for generating nonvolatile skyrmions in a multilayer film. Background technique [0002] Magnetic skyrmion is a kind of magnetic structure with topological behavior. It has particle characteristics, and its size is on the order of nanometers (10-100 nanometers). The spin arrangement of magnetic skyrmions makes the current density driving skyrmion state changes 5-6 orders of magnitude lower than driving conventional magnetic domains, so it is expected to be applied in high-density, high-speed, low-energy magnetic information storage devices. [0003] In the multilayer film material system of the sandwich structure of the first heavy metal layer / ferromagnetic layer / second heavy metal layer (HM1 / FM / HM2), the magnetic moment of the middle ferromagnetic layer (FM) has perpendicular magnetic anisotropy. There is an interfacial spin-orbit coupling effect between the first ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F10/32H01F41/32
CPCH01F10/3236H01F10/3281H01F10/3286H01F41/325
Inventor 张颖何敏李刚蔡建旺谷林沈保根
Owner INST OF PHYSICS - CHINESE ACAD OF SCI