AlNiCo magnetic thin film material with stripe structure and preparation method and application of AlNiCo magnetic thin film material

Abstract

The invention discloses an AlNiCo magnetic thin film material with a stripe structure and a preparation method and application of the AlNiCo magnetic thin film material. The AlNiCo magnetic thin film material with the stripe structure comprises a substrate with stripes on a single face and an AlNiCo thin film covering the face, with the stripes, of the substrate. The preparation method of the AlNiCo magnetic thin film material with the stripe structure comprises the following steps: firstly depositing an AlNiCo thin film on the stripe side of a substrate with stripes on one side, then depositing or not depositing a protective layer on the surface of the AlNiCo thin film, and then carrying out annealing treatment to obtain the AlNiCo magnetic thin film material with the stripe structure. The AlNiCo magnetic thin film material with the stripe structure has the advantages of large residual magnetism, large saturation magnetization intensity, large magnetic energy product, good temperature stability and the like, the preparation method is simple, the production cost is low, and the AlNiCo magnetic thin film material is suitable for large-scale industrial production and application.

Description

Technical Field

[0001] The invention relates to the technical field of magnetic film materials, and in particular to an AlNiCo magnetic film material with a stripe structure and a preparation method and application thereof. Background Art

[0002] With the rapid development of the electronics industry, the miniaturization and integration of electronic components have become an inevitable development trend, but it also brings about serious heat accumulation problems in electronic components. AlNiCo material (also known as aluminum-nickel-cobalt alloy) is a permanent magnetic material with high magnetic properties, high Curie temperature and good temperature stability. It is suitable for high temperature or large temperature change working conditions and is one of the ideal magnetic materials for preparing micro-mechanical components.

[0003] AlNiCo permanent magnet materials belong to the spinodal decomposition type magnets. Their coercivity mainly comes from the nano-spinodal structure produced after the spinodal decomposition phase transition. This structure is composed of iron-cobalt-rich nanorods arranged in an oriented manner, thus forming shape anisotropy. The larger the aspect ratio of the obtained nanorods, the stronger the shape anisotropy, the greater the remanence and coercivity. Therefore, this nano-spinodal structure is crucial to the magnetic properties of AlNiCo magnets, such as coercivity, remanence, and magnetic energy product, and will directly affect the temperature stability of the magnetic properties of AlNiCo magnets. However, for AlNiCo materials in the form of thin films, although AlNiCo thin films can also produce spinodal decomposition phase transitions after heat treatment, the magnetic properties of AlNiCo thin films will be degraded due to the size of nanocrystals and the presence of amorphous regions. On the one hand, nanocrystals limit the range of spinodal decomposition to a very small range, and cannot form a large range of parallel oriented nano-spinodal structures, which results in the coercivity and remanence of AlNiCo thin films being inferior to bulk AlNiCo and difficult to improve. On the other hand, due to the presence of amorphous regions and secondary phases, the saturation magnetization and remanence of AlNiCo films are reduced, which is not conducive to the improvement of the maximum magnetic energy product. Taking the above unfavorable factors into consideration, the remanence and coercive force temperature stability of AlNiCo films are often lower than those of AlNiCo bulk, and their practical applications are greatly limited.

[0004] Therefore, it is of great significance to develop an AlNiCo magnetic thin film material with large remanence, large saturation magnetization, large magnetic energy product and good temperature stability. Summary of the invention

[0005] The purpose of the present invention is to provide an AlNiCo magnetic film material with a stripe structure and a preparation method and application thereof.

[0006] The technical solution adopted by the present invention is:

[0007] An AlNiCo magnetic film material with a stripe structure comprises a substrate with stripes on one side and an AlNiCo film covering the side of the substrate with stripes.

[0008] Preferably, the substrate with stripes on one side is one of a silicon substrate with stripes on one side, a glass substrate with stripes on one side, a quartz substrate with stripes on one side, a ceramic substrate with stripes on one side, and a polymer substrate with stripes on one side.

[0009] Preferably, the stripes on the single-sided striped substrate have a width of 50nm to 2500nm, a depth of 500nm to 5000nm, and a spacing of 50nm to 2500nm.

[0010] Preferably, the aspect ratio of the stripes on the single-sided striped substrate is 2500-8000:1.

[0011] Preferably, a method for preparing the stripes on the substrate with stripes on one side comprises at least one of photolithography, chemical etching, electron beam exposure, and epitaxial growth.

[0012] Preferably, the composition of the AlNiCo film includes one of AlNiCo materials of grades 1-9.

[0013] Preferably, the AlNiCo film has a thickness of 50 nm to 1000 nm.

[0014] Preferably, the surface of the AlNiCo film is also covered with a protective layer.

[0015] Preferably, the protective layer comprises at least one of Cr, Ti, Ta and Ru.

[0016] A method for preparing the AlNiCo magnetic thin film material with a striped structure as described above comprises the following steps: firstly depositing an AlNiCo thin film on the striped side of a single-sided striped substrate, then depositing or not depositing a protective layer on the surface of the AlNiCo thin film, and then performing annealing treatment to obtain the AlNiCo magnetic thin film material with a striped structure.

[0017] Preferably, the AlNiCo film is prepared by one of magnetron sputtering, multi-arc ion plating, pulsed laser deposition, electron beam evaporation, and atomic deposition.

[0018] Preferably, the background vacuum degree during the AlNiCo film deposition process is ≥7×10 -4 Pa, Ar atmosphere is used during deposition, the deposition gas pressure is 0.1Pa~100Pa, and the sputtering deposition power is 20W~200W.

[0019] Preferably, the protective layer is prepared by one of magnetron sputtering, multi-arc ion plating, pulsed laser deposition, electron beam evaporation, and atomic deposition.

[0020] Preferably, the background vacuum degree during the protective layer deposition process is ≥7×10 -4 Pa, Ar atmosphere is used during deposition, the deposition gas pressure is 0.1Pa~100Pa, and the sputtering deposition power is 80W~100W.

[0021] Preferably, the annealing treatment is carried out at a temperature of 500° C. to 700° C., and the holding time is 0.5 h to 5 h.

[0022] Preferably, the annealing treatment is a tube sealing heat treatment, and the tube sealing background vacuum degree is ≥5×10 -2 Pa, the number of air washing is 5 to 10 times.

[0023] A microelectronic device comprises the AlNiCo magnetic film material with a stripe structure.

[0024] Preferably, the microelectronic device is one of a micro inertial navigation device and a micro magnetic encoder.

[0025] An electronic product comprises the above-mentioned microelectronic device.

[0026] The beneficial effects of the present invention are as follows: the AlNiCo magnetic film material with a striped structure has the advantages of large remanence, large saturation magnetization intensity, large magnetic energy product, good temperature stability, etc., and its preparation method is simple and the production cost is low, and it is suitable for large-scale industrial production and application.

[0027] Specifically:

[0028] 1) The AlNiCo magnetic film material with a stripe structure of the present invention introduces shape anisotropy through an artificial stripe structure, so that the remanence, saturation magnetization, maximum magnetic energy product and temperature stability of the AlNiCo magnetic film are significantly improved compared with the planar AlNiCo magnetic film;

[0029] 2) The AlNiCo magnetic thin film material with stripe structure of the present invention has the advantages of large remanence, large saturation magnetization, large magnetic energy product, good temperature stability, etc., and is suitable for use in microelectronic devices (for example: micro inertial navigation devices, micro magnetic encoders, etc.), and has broad application prospects;

[0030] 3) The preparation method of the AlNiCo magnetic thin film material with a striped structure of the present invention is simple and has low production cost, and is suitable for large-scale industrial production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1This is a schematic diagram of the structure of the AlNiCo magnetic thin film material with a striped structure in Example 1.

[0032] Figure 2 This is a schematic diagram of the structure of the AlNiCo magnetic thin film material in Comparative Example 1.

[0033] Figure 3 Demagnetization curves of the AlNiCo magnetic thin film materials in Example 1, Example 2 and Comparative Example 1 at different temperatures.

[0034] Figure 4 The residual magnetization variation curves of the AlNiCo magnetic thin film materials in Example 1, Example 2 and Comparative Example 1 at 200K-400K.

[0035] Figure 5 1 is the coercivity variation curve of the AlNiCo magnetic thin film material in Example 1, Example 2 and Comparative Example 1 at 200K-400K.

[0036] Figure 6 1 is a curve showing the change of saturation magnetization intensity of the AlNiCo magnetic thin film materials in Example 1, Example 2 and Comparative Example 1 at 200K to 400K.

[0037] Figure 7 The maximum magnetic energy product variation curves of the AlNiCo magnetic thin film materials in Example 1, Example 2 and Comparative Example 1 at 200K-400K.

[0038] Figure 8 1 is the XRD diagram of the AlNiCo magnetic thin film material in Example 1, Example 2 and Comparative Example 1. DETAILED DESCRIPTION

[0039] The present invention will be further explained and illustrated below in conjunction with specific embodiments.

[0040] Embodiment 1:

[0041] An AlNiCo magnetic thin film material with a stripe structure, and its preparation method is as follows:

[0042] First, a silicon substrate with stripes on one side was prepared by chemical etching, wherein the width of the stripes was 2000 nm, the depth of the stripes was 500 nm, and the spacing of the stripes was 1500 nm. Then, the silicon substrate with stripes on one side was ultrasonically cleaned with acetone and anhydrous ethanol for 60 min each, then cleaned with deionized water, and dried. Then, an AlNiCo film with a thickness of 310 nm to 340 nm was deposited on the side with stripes by magnetron sputtering. The target material used was an AlNiCo 5 alloy target (processed from a commercial AlNiCo 5 alloy; the mass fraction ratio of the constituent elements was: Fe: 49%; Co: 25%; Ni: 15%; Al: 7%; Cu: 4%). The background vacuum degree during the deposition of the AlNiCo film was ≥7×10 -4 Pa, argon atmosphere was used for deposition, the deposition pressure was 1.8 Pa, the sputtering deposition power was 80 W, the sputtering deposition rate was 11.33 nm / min, the sputtering deposition time was 30 min, and then the obtained parts were sealed, and the vacuum degree during gas washing was ≥5×10 -2 Pa, the number of gas washing is 6 times, a certain amount of argon is filled as protective gas before sealing the tube, and then placed in a muffle furnace for heat treatment, the heat treatment temperature is 650℃, the holding time is 2h, and then taken out for air cooling, and the AlNiCo magnetic thin film material with stripe structure is obtained (the structural schematic diagram is shown in Figure 1 As shown, a is the cross section and b is the surface).

[0043] Embodiment 2:

[0044] An AlNiCo magnetic thin film material with a striped structure is identical to Example 1 except that the width of the stripes on the single-sided striped silicon substrate is adjusted from "2000nm" to "2500nm" during preparation.

[0045] Comparative Example 1:

[0046] An AlNiCo magnetic film material (structural schematic diagram as shown in Figure 2 ; cross section), except that the "single-sided striped silicon substrate" is replaced by a "flat glass substrate" during preparation, the rest is exactly the same as Example 1.

[0047] Performance Test:

[0048] 1) Demagnetization curves of the AlNiCo magnetic thin film materials in Example 1, Example 2 and Comparative Example 1 at different temperatures are shown in FIG. Figure 3 As shown in the figure, the residual magnetism change curve at 200K~400K is as follows Figure 4 As shown in the figure, the coercivity curve at 200K~400K is as follows Figure 5 As shown in the figure, the saturation magnetization intensity variation curve at 200K~400K is as follows Figure 6As shown in the figure, the maximum magnetic energy product variation curve at 200K~400K is as follows Figure 7 shown.

[0049] Note: The temperature stability of magnetic properties of magnets generally includes two aspects, namely, the temperature stability of remanence and the temperature stability of coercivity. The temperature stability of remanence is quantified by the temperature coefficient of remanence (α), and the temperature stability of coercivity of magnets is quantified by the temperature coefficient of coercivity (β). The expressions are respectively formula (1) and formula (2):

[0050] Formula (1):

[0051] Formula (2):

[0052] In the above formula, M r (T0) and M r (T1) are the remanence values ​​at T0 and T1 respectively, H r (T0) and H r (T1) are the coercive force values ​​at temperatures T0 and T1, respectively.

[0053] Depend on Figures 3 to 7 It can be seen that:

[0054] a) The remanence, saturation magnetization and maximum magnetic energy product of the striped AlNiCo magnetic film materials in Examples 1 and 2 are significantly higher than those of the AlNiCo magnetic film material (planar AlNiCo film) in Comparative Example 1; at room temperature, the remanence of the AlNiCo magnetic film material in Comparative Example 1 is only 3.7 kGs, while the remanence of the striped AlNiCo magnetic film material in Example 1 reaches 4.6 kGs, with a remanence increase of 24.3%, and the remanence of the striped AlNiCo magnetic film material in Example 2 reaches 4.2 kGs, with a remanence increase of 13.5%; the saturation magnetization of the AlNiCo magnetic film material in Comparative Example 1 is 6.37kGs, while the saturation magnetization intensity of the AlNiCo magnetic film material with a striped structure in Example 1 reaches 7.56kGs, an increase of 18.7%, and the saturation magnetization intensity of the AlNiCo magnetic film material with a striped structure in Example 2 reaches 7.29kGs, an increase of 14.4%; the maximum magnetic energy product of the AlNiCo magnetic film material in Comparative Example 1 is 0.76MGOe, while the maximum magnetic energy product of the AlNiCo magnetic film material with a striped structure in Example 1 is 0.94MGOe, an increase of 23.7%, and the maximum magnetic energy product of the AlNiCo magnetic film material with a striped structure in Example 2 is 0.80MGOe, an increase of 5.3%;

[0055] b) The remanence temperature coefficient and coercivity temperature coefficient of the AlNiCo magnetic film material in comparative example 1 are -0.0676% / K and -0.0980% / K respectively, while the remanence temperature coefficient and coercivity temperature coefficient of the AlNiCo magnetic film material with a striped structure in Example 1 are -0.0534% / K and -0.0888% / K respectively, and the remanence temperature stability and coercivity temperature stability thereof are improved by 21.0% and 9.4% respectively. The remanence temperature coefficient and coercivity temperature coefficient of the AlNiCo magnetic film material with a striped structure in Example 2 are -0.0524% / K and -0.0684% / K respectively, and the remanence temperature stability and coercivity temperature stability thereof are improved by 22.5% and 30.2% respectively. It is obvious that the remanence temperature stability and coercivity temperature stability of the AlNiCo magnetic film materials with a striped structure in Examples 1 and 2 are higher.

[0056] 2) X-ray diffraction (XRD) patterns of the AlNiCo magnetic thin film materials in Example 1, Example 2 and Comparative Example 1 are as follows: Figure 8 shown.

[0057] Depend on Figure 8 It can be seen that the main phase compositions of the AlNiCo magnetic film materials in Example 1, Example 2 and Comparative Example 1 are similar, all of which are FeCo-rich phases and AlNi3-rich phases obtained by the phase transformation of the amplitude modulation decomposition. After the introduction of the artificially designed stripe structure, the AlNiCo film has a shape anisotropy similar to that of the bulk AlNiCo material, which ultimately improves the remanence of the film along the stripe direction, thereby facilitating the improvement of the maximum magnetic energy product. Regarding the temperature stability of remanence and coercive force, due to the anisotropy of the stripe film, the demagnetization factor is smaller in the long axis direction of the stripe, and the film is easy to produce spontaneous magnetization along the long axis direction, that is, the magnetization magnetic field in this direction is more stable, which is conducive to improving its remanence and coercive force temperature stability. In addition, the introduction of the artificially designed stripe structure also has a certain effect on its phase change, inhibiting the formation of the non-magnetic phase AlNi3 phase, lacking the pinning effect of the non-magnetic AlNi3 phase, resulting in a decrease in the coercive force of the stripe film, but at the same time it is also conducive to the improvement of the remanence and saturation magnetization.

[0058] Embodiment 3:

[0059] An AlNiCo magnetic thin film material with a stripe structure, and its preparation method is as follows:

[0060] First, a single-sided striped silicon substrate (size 4mm×4mm) was prepared by chemical etching, the stripe width was 1500nm, the stripe depth was 500nm, the stripe spacing was 1500nm, and the stripe length was 4mm (the aspect ratio of the stripe was 2667:1, corresponding to the ratio of the side length to the width of the substrate was 1:1). Then, the single-sided striped silicon substrate was ultrasonically cleaned with acetone and anhydrous ethanol for 60min each, then cleaned with deionized water and dried. Then, a magnetron sputtering method was used to deposit an AlNiCo film with a thickness of about 310nm on the striped side of the substrate. The target material used was an AlNiCo 5 alloy target (obtained from commercial AlNiCo 5 alloy; the mass fraction ratio of the constituent elements was: Fe: 49%; Co: 25%; Ni: 15%; Al: 7%; Cu: 4%). The background vacuum degree during the deposition of the AlNiCo film was ≥7×10 -4 Pa, argon atmosphere was used for deposition, the deposition pressure was 1.8 Pa, the sputtering deposition power was 80 W, the sputtering deposition rate was 11.33 nm / min, the sputtering deposition time was 30 min, and then the obtained parts were sealed, and the vacuum degree during gas washing was ≥5×10 -2 Pa, the purge times are 6 times, a certain amount of argon is filled as a protective gas before sealing the tube, and then placed in a muffle furnace for heat treatment, the heat treatment temperature is 650 ° C, the insulation time is 2h, and then taken out for air cooling, and the AlNiCo magnetic thin film material with a striped structure is obtained.

[0061] Embodiment 4:

[0062] An AlNiCo magnetic thin film material with a striped structure is exactly the same as Example 3 except that the size of the single-sided striped silicon substrate is adjusted from "4mm×4mm" to "4mm×8mm" and the length of the stripe is adjusted from "4mm" to "8mm" (the aspect ratio of the stripe is 5333:1, and the ratio of the side length to the width of the corresponding substrate is 2:1).

[0063] Embodiment 5:

[0064] An AlNiCo magnetic thin film material with a striped structure is exactly the same as Example 3 except that the size of the single-sided striped silicon substrate is adjusted from "4mm×4mm" to "4mm×12mm" and the length of the stripe is adjusted from "4mm" to "12mm" (the aspect ratio of the stripe is 8000:1, and the ratio of the side length to the width of the corresponding substrate is 3:1).

[0065] Comparative Example 2:

[0066] An AlNiCo magnetic thin film material is exactly the same as Example 3 except that the "single-sided striped silicon substrate" is replaced by a "flat glass substrate" of the same size during preparation.

[0067] Performance Test:

[0068] The remanence change test data, coercivity change test data, saturation magnetization change test data and maximum magnetic energy product change test data of the AlNiCo magnetic film materials in Examples 3 to 5 and Comparative Example 2 in the temperature range of 200K to 400K are shown in the following table:

[0069] Table 1 Remanence change test data

[0070]

[0071]

[0072] Table 2 Coercivity change test data

[0073] Hc 200k(Oe) 300k(Oe) 400k(Oe) Temperature coefficient (% / K) Comparative Example 2 606.09 578.20 528.55 -0.06397 Example 3 564.38 511.64 476.95 -0.07746 Example 4 548.50 494.02 457.41 -0.08304 Example 5 571.15 514.50 492.66 -0.06871

[0074] Table 3 Saturation magnetization intensity change test data

[0075] Ms 200k(kGs) 300k(kGs) 400k(kGs) Comparative Example 2 6.55 6.41 6.21 Example 3 6.84 6.73 6.50 Example 4 6.64 6.49 6.28 Example 5 6.64 6.66 6.57

[0076] Table 4 Maximum energy product change test data

[0077] <![CDATA[BH (max) ]]> 200k(MGOe) 300k(MGOe) 400k(MGOe) Comparative Example 2 0.91 0.78 0.74 Example 3 1.18 1.09 0.86 Example 4 1.28 1.09 0.92 Example 5 1.37 1.24 1.02

[0078] From Tables 1 to 4, we can see that:

[0079] a) The AlNiCo magnetic thin film materials in Examples 3 to 5 have improved saturation magnetization, remanence and maximum magnetic energy product, while decreased coercivity, compared with the AlNiCo magnetic thin film material in Comparative Example 2;

[0080] b) When the stripe aspect ratio is higher than 5333:1 (the AlNiCo magnetic film material in Example 4), the remanent magnetization temperature stability of the AlNiCo magnetic film material is better than that of the planar film (the AlNiCo magnetic film material in Comparative Example 2);

[0081] c) The higher the stripe aspect ratio, the higher the remanence and maximum magnetic energy product of the AlNiCo magnetic film material, both of which reach the highest when the stripe aspect ratio is 8000:1 (the AlNiCo magnetic film material in Example 5), while the coercive force and saturation magnetization first decrease and then increase; the AlNiCo magnetic film material in Example 5 has a remanence increase of 26.6% and a maximum magnetic energy product increase of 59.0% compared with the planar film (the AlNiCo magnetic film material in Comparative Example 2);

[0082] d) The introduction of such a stripe structure is beneficial to improving the remanent magnetization temperature stability of the film, and the temperature stability increases with the increase of the aspect ratio. When the stripe aspect ratio is 8000:1 (the AlNiCo magnetic film material in Example 5), the remanent magnetization temperature stability is optimal, and the remanent magnetization temperature stability is improved by 11.5% relative to the planar film (the AlNiCo magnetic film material in Comparative Example 2);

[0083] In summary, increasing the stripe aspect ratio is beneficial to improving the comprehensive properties of AlNiCo magnetic thin film materials.

[0084] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. An AlNiCo magnetic thin film material with a stripe structure, characterized in that: The composition includes a substrate with stripes on one side and an AlNiCo film covering the striped side of the substrate.

2. The AlNiCo magnetic thin film material with a striped structure according to claim 1, characterized in that: The substrate with stripes on one side is one of a silicon substrate with stripes on one side, a glass substrate with stripes on one side, a quartz substrate with stripes on one side, a ceramic substrate with stripes on one side, and a polymer substrate with stripes on one side.

3. The AlNiCo magnetic thin film material with a striped structure according to claim 1 or 2, characterized in that: The stripes on the single-sided striped substrate have a width of 50nm to 2500nm, a depth of 500nm to 5000nm, and a spacing of 50nm to 2500nm.

4. The AlNiCo magnetic thin film material with a striped structure according to claim 1, characterized in that: The composition of the AlNiCo film includes one of the AlNiCo materials of grades 1-9.

5. The AlNiCo magnetic thin film material with a striped structure according to claim 1 or 4, characterized in that: The thickness of the AlNiCo film is 50nm-1000nm.

6. The AlNiCo magnetic thin film material with a striped structure according to any one of claims 1, 2 and 4, characterized in that: The surface of the AlNiCo film is also covered with a protective layer.

7. The AlNiCo magnetic thin film material with a striped structure according to claim 6, characterized in that: The protective layer is composed of at least one of Cr, Ti, Ta and Ru.

8. A method for preparing an AlNiCo magnetic thin film material with a striped structure as claimed in any one of claims 1 to 7, characterized in that: The following steps are involved: Firstly, an AlNiCo film is deposited on the striped side of a single-sided striped substrate, and then a protective layer is deposited or not deposited on the surface of the AlNiCo film, and then annealing is performed to obtain an AlNiCo magnetic film material with a striped structure.

9. A microelectronic device, characterized in that: An AlNiCo magnetic thin film material with a striped structure comprising any one of claims 1 to 7.

10. An electronic product, characterized in that: A microelectronic device comprising the microelectronic device of claim 9.

Images