All-optical magnetic recording device
By stacking one-dimensional periodic photonic crystals and silicon dioxide intercalation layers in the all-optical magnetic recording device, a resonant cavity is formed to efficiently absorb femtosecond lasers, which solves the problem of low utilization rate of femtosecond pump lasers, and achieves low power consumption and ultra-fast all-optical magnetic storage.
Patent Information
- Application Number
- CN202510266601.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-07
- Publication Date
- 2025-06-27
AI Technical Summary
Since the thickness of the spintronic all-optical magnetic recording film is small, the femtosecond pump laser is easy to pass through directly, resulting in a low energy utilization rate, limiting the application of all-optical magnetic reversal technology.
One-dimensional periodic photonic crystals, silicon dioxide interpolation and spintron all-optical magnetic recording films are stacked on the substrate in turn. By regulating the thickness of the photonic crystal element layer and the thickness of the silicon dioxide interpolation, a resonant cavity is formed to achieve efficient absorption of femtosecond lasers.
Theoretically, the femtosecond laser absorption rate can reach 100%, which improves the interaction between femtosecond pump laser and spintron full-optomagnetic recording film, lowers the spintron flip threshold, and achieves low-power consumption and ultra-fast full-optomagnetic storage.
Smart Images
Figure CN120220765A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure belongs to the technical field of magneto-optical storage, and particularly relates to an all-optical magnetic recording device. Background Art
[0002] The all-optical magnetic reversal technology directly uses ultrafast laser pulses to control the spin direction without the need for current and magnetic fields. However, since the spin-electronic all-optical magnetic recording thin film is generally only dozens of nanometers thick, most of the femtosecond pump lasers directly pass through the spin magnetic recording thin film, resulting in low energy utilization efficiency of the femtosecond laser. Summary of the Invention
[0003] In view of the problems in the background art, the present disclosure proposes an all-optical magnetic recording device.
[0004] To achieve the above object, the present disclosure adopts the following technical solutions:
[0005] An all-optical magnetic recording device includes a substrate, on one side of which are sequentially stacked a one-dimensional periodic photonic crystal, a silica interlayer, and a spin-electronic all-optical magnetic recording thin film; wherein, the one-dimensional periodic photonic crystal is composed of multiple one-dimensional photonic crystal primitive layers stacked, and the one-dimensional photonic crystal primitive includes a silicon nitride layer and a silica layer.
[0006] Further, the substrate is a quartz substrate.
[0007] Further, the number of the one-dimensional photonic crystal primitives is 10 - 25.
[0008] Further, the material of the spin-electronic all-optical magnetic recording thin film includes ferrimagnetism.
[0009] Further, the spin-electronic all-optical magnetic recording thin film is grown on the silica interlayer by magnetron sputtering, and the silica interlayer is prepared on the one-dimensional photonic crystal primitive by chemical vapor deposition.
[0010] Further, the material of the spin-electronic all-optical magnetic recording thin film includes GdCo.
[0011] Further, the material of the spin-electronic all-optical magnetic recording thin film includes GdFeCo.
[0012] Further, the refractive index of the silica layer is 1.446, the refractive index of the silicon nitride layer is 2.112, the thickness of the silica layer is 118.1 nm, the thickness of the silicon nitride layer is 109.5 nm, and the thickness of the silica interlayer is 144 nm.
[0013] Further, the spin - electron all - optical magnetic recording thin film includes, from top to bottom in sequence: a first Pt layer, a GdCo layer, a second Pt layer, and a Ta layer; wherein, the ratio of Gd to Co is 0.2:0.8, the thicknesses of the first Pt layer, the second Pt layer, and the Ta layer are all 2 nm, and the thickness of the GdCo layer is 8 nm.
[0014] Further, the number of periods of the one - dimensional photonic crystal unit is 20.
[0015] Advantages of the present disclosure:
[0016] The method of the present disclosure stacks a one - dimensional periodic photonic crystal, a silica interlayer, and a spin - electron all - optical magnetic recording thin film on a substrate in sequence. During use, by adjusting the thickness of the one - dimensional periodic photonic crystal unit layer and the thickness of the silica interlayer between the one - dimensional periodic photonic crystal and the spin - electron all - optical magnetic recording thin film, when a certain phase - matching adjustment is satisfied, a resonant cavity can be formed at the silica interlayer, thereby achieving efficient absorption of femtosecond laser. Theoretically, the femtosecond laser absorption rate can reach 100%, thus enhancing the interaction between the femtosecond pump laser and the spin - electron all - optical magnetic recording thin film, reducing the spin - electron flipping threshold of the spin - electron all - optical magnetic recording thin film, and providing an effective technical means for realizing low - power and ultrafast all - optical magnetic storage. In addition, due to the introduction of the one - dimensional periodic photonic crystal, the method of reading the state of the spin - electron thin film through the magneto - optical Kerr effect becomes more flexible. It can be read from one side of the spin - electron all - optical magnetic recording thin film or from the substrate side, improving the flexibility.
[0017] Other features and advantages of the present disclosure will be described in the following description of the specification, and some of them will become obvious from the description of the specification, or can be understood by implementing the present disclosure. The objectives and other advantages of the present disclosure can be achieved and obtained through the structures pointed out in the specification and the drawings. Description of the Drawings
[0018] To more clearly illustrate the technical solutions in the embodiments of the present disclosure or in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following - described drawings are some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.
[0019] Figure 1 Shows a schematic diagram of an all - optical magnetic recording device of the present disclosure;
[0020] Figure 2 Shows the absorption rates of the measured traditional all - optical magnetic recording thin film (GdCo), the all - optical magnetic recording device (GdCo / DBR), and the simple one - dimensional photonic crystal (DBR) of the present disclosure at different wavelengths;
[0021] Figure 3 Shows the optical switching of traditional all-optical magnetic recording and the efficient magnetic recording method of the present disclosure at different energy densities measured by a static magneto-optical Kerr device;
[0022] Figure 4 (a) Shows the spin flipping dynamics process of a traditional magnetic recording thin film measured by a time-resolved magneto-optical Kerr measuring instrument of the present disclosure;
[0023] Figure 4 (b) Shows the spin flipping dynamics process of the present disclosure.
[0024] In the figure: 101, substrate; 102, one-dimensional periodic photonic crystal; 103, silica interlayer; 104, spin-electronic all-optical magnetic recording thin film. Detailed implementation manners
[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present disclosure. Apparently, the described embodiments are some but not all of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present disclosure without creative efforts shall fall within the protection scope of the present disclosure.
[0026] Traditional hard disk magnetic storage technology relies on the magnetic field generated by the magnetic head to control the direction of spin electrons in the magnetic recording thin film, thereby realizing data writing and erasing. In this mechanism, the electron spin reverses direction through precession, and this process usually takes several nanoseconds, which limits the speed of magnetic recording. In contrast, all-optical magnetic reversal is a novel spin control technology that does not require current or magnetic field, but directly uses ultrafast laser pulses to control the spin direction. The advantages of this technology include faster writing speed, extremely low writing energy consumption, and lower error rate.
[0027] However, since the spin-electronic all-optical magnetic recording thin film used for magnetic recording is usually only dozens of nanometers thick, most of the femtosecond pump laser will directly penetrate the thin film, resulting in low energy utilization rate, which limits the application of all-optical magnetic reversal technology.
[0028] To solve the above problems, the present disclosure proposes an all-optical magnetic recording device, referring to Figure 1As shown in the figure, the all-optical magnetic recording device includes: a substrate 101, on one side of which are sequentially stacked a one-dimensional periodic photonic crystal 102, a silica interlayer 103, and a spintronic all-optical magnetic recording thin film 104; among them, the one-dimensional periodic photonic crystal 102 is composed of multiple one-dimensional photonic crystal primitive layers stacked, and the one-dimensional photonic crystal primitive includes a silicon nitride layer and a silica layer. As a preferred embodiment of the present disclosure, the substrate 101 is a quartz substrate. It should be further noted that Figure 1 in this case, the silica layer is close to the substrate. However, the silicon nitride layer can also be designed to be close to the substrate, and the present disclosure does not limit this.
[0029] By sequentially stacking the one-dimensional periodic photonic crystal 102, the silica interlayer 103, and the spintronic all-optical magnetic recording thin film 104 on the substrate 101, during use, by adjusting the thickness of the one-dimensional photonic crystal primitive layer and the thickness of the silica interlayer between the one-dimensional periodic photonic crystal 102 and the spintronic all-optical magnetic recording thin film 104, when a certain phase matching adjustment is satisfied, a resonant cavity can be formed at the silica interlayer, thereby realizing the efficient absorption of femtosecond laser. Theoretically, the femtosecond laser absorption rate can reach 100%, so as to enhance the interaction between the femtosecond pump laser and the spintronic all-optical magnetic recording thin film, reduce the spin electron flipping threshold of the spintronic all-optical magnetic recording thin film, and provide an effective technical means for realizing low-power, ultrafast all-optical magnetic storage.
[0030] In addition, due to the introduction of the one-dimensional periodic photonic crystal 102, the method of reading the state of the spintronic all-optical magnetic recording thin film 104 through the magneto-optical Kerr effect becomes more flexible. It can be read from one side of the spintronic all-optical magnetic recording thin film or from the side of the substrate, improving the flexibility.
[0031] As a preferred embodiment of the present disclosure, the number of one-dimensional photonic crystal primitives is 10 - 25.
[0032] As a preferred embodiment of the present disclosure, the main component of the spintronic all-optical magnetic recording thin film 104 is a ferrimagnetic material, such as GdCo or GdFeCo, and the spintronic all-optical magnetic recording thin film 104 is grown on the silica interlayer by magnetron sputtering.
[0033] As a preferred embodiment of the present disclosure, the silica interlayer 103 is prepared on the one-dimensional photonic crystal primitive by chemical vapor deposition.
[0034] In a specific embodiment, taking the material of the spintronic all-optical magnetic recording thin film 104 as GdCo for example, a femtosecond laser with a central wavelength of 800 nm is incident on the high-efficiency all-optical magnetic recording device from the upper air layer. In this example, the refractive indices of silicon dioxide and silicon nitride are 1.446 and 2.112 respectively, and the thicknesses are 118.1 nm and 109.5 nm respectively; the thickness of the silicon dioxide interlayer is 144 nm; the specific composition of the spintronic all-optical magnetic recording thin film 104 is Pt(2 nm) / Gd 0.2 Co 0.8 (8 nm) / Pt(2 nm) / Ta(2 nm), where the values in parentheses are the thicknesses of each layer, and the subscript of GdCo indicates that the ratio of Gd and Co is 0.2:0.8. The first Pt layer serves as an anti-oxidation layer, the second Pt layer is used to achieve the perpendicular magnetic anisotropy of GdCo, the Ta layer serves as a buffer layer, and the number of periods N of the one-dimensional photonic crystal unit is 20. Figure 2 The traditional all-optical magnetic recording thin film (GdCo) measured in this embodiment. The absorption rates of the high-efficiency magnetic recording device (GdCo / DBR) based on one-dimensional photonic crystals and the pure one-dimensional photonic crystal (DBR) of the present disclosure at different wavelengths. It can be seen that in the 800 nm band, the light absorption rate of the high-efficiency magnetic recording device based on one-dimensional photonic crystals is greater than 87%, far higher than the absorption efficiency of 41% of the traditional all-optical magnetic recording thin film. At the same time, it can be seen that the light absorption all comes from the spintronic all-optical magnetic recording thin film 104, and the one-dimensional periodic photonic crystal 102 basically has no light absorption.
[0035] Refer to Figure 3 As shown, it shows the spin electron flipping situation of the all-optical magnetic recording thin film under different energy densities measured by a static magneto-optical Kerr device; among them, the gray area represents the initial magnetization direction of the spin electrons, and the black area represents that after being irradiated by the femtosecond laser, the magnetic moment of the spin electrons has flipped. It can be seen that when the pump energy is 0.21 mJ / cm 2 , the spin electrons in the high-efficiency magnetic recording device based on one-dimensional photonic crystals proposed by the present disclosure have already started to flip. When the pump energy increases to 1.06 mJ / cm 2 , the magnetic moment is basically all flipped (the irregularity of the flipped magnetic moment is due to the irregular shape of the pump light spot). For the traditional GdCo thin film, it doesn't start to flip until the pump energy is 0.43 mJ / cm 2 , and when the pump energy is 1.27 mJ / cm 2 , its magnetic moment has not all flipped yet. It should be noted that the structure and parameters of the traditional GdCo thin film in this comparative experiment are exactly the same as those of the GdCo thin film in the high-efficiency magnetic recording based on one-dimensional photonic crystals. Therefore, the high-efficiency all-optical magnetic recording device based on one-dimensional photonic crystals proposed by the present disclosure can significantly reduce the power consumption of spin electron flipping. At the same time, byFigure 3 It can be seen that the all-optical magnetic recording device has good repeatability, that is, when subjected to the second optical pumping pulse, the spin electrons can be flipped again to erase information.
[0036] Refer to Figure 4 As shown, it can be seen that for the traditional GdCo thin film, the pump energy increases from 0.65 mJ / cm 2 to 1.25 mJ / cm 2 , and the magnetic moment does not reach the flipping threshold until 0.95 mJ / cm 2 . For the high-efficiency magnetic recording method based on one-dimensional photonic crystals, the critical threshold for magnetic moment flipping is 0.75 mJ / cm 2 , and the flipping threshold is reduced by nearly 1 time.
[0037] It should be noted that in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.
[0038] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
[0039] Although the present disclosure has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.
Claims
1. An all-optical magnetic recording device, characterized in that: It includes a substrate, one side of which is stacked with a one-dimensional periodic photonic crystal, a silicon dioxide intercalation layer and a spin electronic all-optical magnetic recording film in sequence; wherein the one-dimensional periodic photonic crystal is composed of a plurality of one-dimensional photonic crystal primitives stacked in layers, and the one-dimensional photonic crystal primitives include a silicon nitride layer and a silicon dioxide layer.
2. The all-optical magnetic recording device according to claim 1, characterized in that: The substrate is a quartz substrate.
3. The all-optical magnetic recording device according to claim 1, characterized in that: The number of the one-dimensional photonic crystal primitives is 10-25.
4. The all-optical magnetic recording device according to claim 1, characterized in that: The material of the spin electron all-optical magnetic recording film includes ferrimagnetism.
5. The all-optical magnetic recording device according to claim 1, characterized in that: The spin electron all-optical magnetic recording film is grown on the silicon dioxide intercalation layer by magnetron sputtering, and / or the silicon dioxide intercalation layer is prepared on the one-dimensional photonic crystal unit by vapor deposition.
6. The all-optical magnetic recording device according to claim 4, characterized in that: The material of the spintronic all-optical magnetic recording film includes GdCo.
7. The all-optical magnetic recording device according to claim 4, characterized in that: The material of the spintronic all-optical magnetic recording film includes GdFeCo.
8. The all-optical magnetic recording device according to claim 6, characterized in that: The refractive index of the silicon dioxide layer is 1.446, the refractive index of the silicon nitride layer is 2.112, the thickness of the silicon dioxide layer is 118.1 nm, the thickness of the silicon nitride layer is 109.5 nm, and the thickness of the silicon dioxide intercalation layer is 144 nm.
9. The all-optical magnetic recording device according to claim 8, characterized in that: The spin electron all-optical magnetic recording film includes, from top to bottom, a first Pt layer, a GdCo layer, a second Pt layer and a Ta layer; wherein the ratio of Gd to Co is 0.2:0.8, the thicknesses of the first Pt layer, the second Pt layer and the Ta layer are all 2nm, and the thickness of the GdCo layer is 8nm.
10. The all-optical magnetic recording device according to claim 9, characterized in that: The period number of the one-dimensional photonic crystal unit is 20.