Treatment method for improving ferromagnetic resonance line width of spinel NiZn ferrite single crystal pellets

Abstract

The invention relates to the technical field of ferrite single-crystal materials, in particular to a treatment method for improving the ferromagnetic resonance line width of spinel NiZn ferrite single-crystal pellets, which comprises the following steps: annealing the spinel NiZn ferrite single-crystal pellets under the conditions of high oxygen pressure and high temperature, slowly cooling to room temperature, and releasing the pressure after the annealing is finished, thereby obtaining the spinel NiZn ferrite single-crystal pellets. According to the method, the NiZn ferrite single crystal pellets are subjected to annealing treatment by adopting a high-oxygen-pressure high-temperature annealing treatment process, the pellet processing stress can be released under the condition of inhibiting Zn element volatilization, the ferromagnetic resonance line width of the NiZn ferrite single crystal pellets can be effectively reduced, and subsequent pellet surface polishing treatment is also facilitated.

Description

Technical Field

[0001] This invention relates to the field of ferrite single crystal materials technology, specifically to a method for improving the ferromagnetic resonance linewidth of spinel NiZn ferrite single crystal microspheres. Background Technology

[0002] Spinel-type NiZn ferrite single crystal material is a subferromagnetic material with excellent characteristics such as high saturation magnetization intensity and wide coverage, and narrow ferromagnetic resonance linewidth. It is a high-performance gyromagnetic microwave ferrite material and is widely used in various high-Q, low-insertion-loss ferrite filter devices.

[0003] NiZn ferrite single crystal materials are typically processed into single-crystal spheres for use in devices. However, the machining process inflicts significant processing stress on these spheres, which not only increases the ferromagnetic resonance linewidth but also affects the effectiveness of subsequent surface polishing. For ordinary ferrite single crystal materials, this processing stress can be released through annealing. However, NiZn ferrite single crystal spheres contain highly volatile Zn, and traditional high-temperature annealing causes Zn volatilization, resulting in a significant increase in the ferromagnetic resonance linewidth of the spheres. Summary of the Invention

[0004] The purpose of this invention is to provide a method for improving the ferromagnetic resonance linewidth of spinel NiZn ferrite single crystal microspheres, thereby solving the technical problem in the prior art where high-temperature annealing of spinel NiZn ferrite single crystal microspheres leads to element volatilization and an increase in ferromagnetic resonance linewidth.

[0005] This invention discloses a method for improving the ferromagnetic resonance linewidth of spinel NiZn ferrite single crystal microspheres, comprising the following steps: Spinel NiZn ferrite single crystal microspheres are annealed under high oxygen pressure and high temperature conditions, and then slowly cooled to room temperature. After annealing, the pressure is released to obtain the product.

[0006] This invention employs a high-oxygen-pressure, high-temperature annealing process to anneal NiZn ferrite single-crystal microspheres. This method can release the processing stress of the microspheres while suppressing the volatilization of Zn, which can not only effectively reduce the ferromagnetic resonance linewidth of the NiZn ferrite single-crystal microspheres, but also facilitate subsequent surface polishing of the microspheres.

[0007] Furthermore, under high oxygen pressure and high temperature conditions, the oxygen partial pressure is PO2 = 6MPa~8MPa.

[0008] Furthermore, under high oxygen pressure and high temperature conditions, the oxygen partial pressure is PO2 = 6MPa, 7MPa, or 8MPa.

[0009] Furthermore, under high oxygen pressure and high temperature conditions, the temperature is maintained at 800℃~1000℃ for 15h to 20h.

[0010] Furthermore, the annealing cooling conditions are 10℃ / h to 20℃ / h.

[0011] Furthermore, the rate of pressure release is 0.5 MPa to 1 MPa per minute.

[0012] Furthermore, the spinel NiZn ferrite single crystal microspheres are placed in a platinum boat for annealing.

[0013] Furthermore, the platinum boat is located in the central region of the annealing furnace during early annealing.

[0014] Furthermore, the annealing furnace is sealed during annealing.

[0015] A spinel NiZn ferrite single crystal microsphere was prepared using the method described above.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention employs a high oxygen pressure and high temperature annealing process to anneal NiZn ferrite single crystal microspheres. This method can release the processing stress of the microspheres while suppressing the volatilization of Zn, which can not only effectively reduce the ferromagnetic resonance linewidth of NiZn ferrite single crystal microspheres by about 1 / 3 (from an average of about 12 Oe to about 8 Oe), but also facilitate subsequent polishing of the microsphere surface. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 The results of ferromagnetic resonance linewidth measurement of NiZn ferrite single crystal microspheres before annealing treatment; Figure 2 The results of the ferromagnetic resonance linewidth test of NiZn ferrite single crystal microspheres after annealing in Example 1 are shown. Figure 3 The results of ferromagnetic resonance linewidth measurement of NiZn ferrite single crystal microspheres after annealing in Comparative Example 1 are shown. Figure 4 The results show the ferromagnetic resonance linewidth measurements of NiZn ferrite single crystal microspheres after annealing in Comparative Example 2. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them.

[0020] Example 1 This embodiment discloses a method for improving the ferromagnetic resonance linewidth of spinel NiZn ferrite single crystal microspheres, including the following steps: First, 20 NiZn ferrite single crystal microspheres obtained through machining were selected. The microspheres were cleaned with alcohol and deionized water, and the ferromagnetic resonance linewidth of each microsphere was measured and recorded using a ferromagnetic resonance linewidth measurement system. The selected NiZn ferrite single crystal microspheres were then placed in an annealing platinum boat and placed in the central area of ​​a high-temperature, high-pressure annealing furnace, which was sealed using a metal flange. High-purity oxygen was then introduced into the furnace, and the oxygen partial pressure was set to 7 MPa. Next, the heating and cooling process curves of the high-temperature, high-pressure annealing furnace were set. First, the temperature was raised from room temperature to 800℃ within 4 hours and held at 800℃ for 20 hours. Then, the temperature was slowly lowered to room temperature at a rate of 10℃ / h. Finally, the oxygen pressure was slowly released at a rate of 0.5 MPa per minute until it reached atmospheric pressure. The sealing flange was then opened, and the single crystal microspheres were removed. After rinsing the single crystal microspheres with deionized water, the ferromagnetic resonance linewidth of each single crystal microsphere was measured and recorded using a ferromagnetic resonance linewidth testing system.

[0021] Figure 1 The results show the ferromagnetic resonance linewidth of NiZn ferrite single crystal microspheres before high-temperature annealing. Figure 2 The results of the ferromagnetic resonance linewidth test after high oxygen pressure and high temperature annealing show that the ferromagnetic resonance linewidth at 10 GHz frequency decreased from 13.40 Oe to 7.44 Oe after the high oxygen pressure and high temperature annealing treatment, which is a significant reduction in ferromagnetic resonance linewidth.

[0022] Example 2 Compared with Example 1, the only change in this embodiment is that "high-purity oxygen is introduced and the oxygen partial pressure is set to 6 MPa. The temperature is maintained at 1000°C for 15 hours, and then the temperature is slowly reduced at a rate of 20°C / h". The rest is the same as Example 1.

[0023] The NiZn ferrite single crystal microspheres obtained by annealing in Example 2 showed a significant reduction in ferromagnetic resonance linewidth at 10 GHz, decreasing from 14.0 Oe to 7.6 Oe.

[0024] Comparative Example 1 Compared with Example 1, the only change in this comparative example is that "high-purity oxygen is introduced and the oxygen partial pressure is set to 0.1 MPa", and the rest is the same as Example 1.

[0025] like Figure 3 As shown, the NiZn ferrite single crystal microspheres obtained by annealing in Comparative Example 1 have a ferromagnetic resonance linewidth of approximately 15.38 Oe at a frequency of 10 GHz, which is significantly larger than the ferromagnetic resonance linewidth of the single crystal material obtained in Example 1.

[0026] Comparative Example 2 Compared with Example 1, the only change in this comparative example is that "the temperature is then slowly reduced at a rate of 40°C / h", and the rest is the same as Example 1.

[0027] like Figure 4 As shown, the NiZn ferrite single crystal microspheres obtained from Comparative Example 2 have a ferromagnetic resonance linewidth of approximately 12.74 Oe at a frequency of 10 GHz, which is significantly larger than the ferromagnetic resonance linewidth of the single crystal material obtained in Example 1.

[0028] Comparative Example 3 The only difference between this comparative example and Example 1 is that it is kept at 600°C for 20 hours; the rest is the same as Example 1.

[0029] The NiZn ferrite single crystal microspheres obtained from Comparative Example 3 have a ferromagnetic resonance linewidth of approximately 14.95 Oe at a frequency of 10 GHz, which is significantly larger than the ferromagnetic resonance linewidth of the single crystal material obtained in Example 1.

[0030] Comparative Example 4 The only difference between this comparative example and Example 1 is that it was kept at 1200°C for 20 hours; the rest is the same as Example 1.

[0031] The NiZn ferrite single crystal microspheres obtained from Comparative Example 4 have a ferromagnetic resonance linewidth of approximately 17.62 Oe at a frequency of 10 GHz, which is significantly larger than the ferromagnetic resonance linewidth of the single crystal material obtained in Example 1.

[0032] The statistical average value of the ferromagnetic resonance linewidth of the single-crystal materials grown in Examples 1 and 2 and Comparative Examples 1, 2, 3, and 4 was measured. Each experiment involved 30 NiZn ferrite single-crystal microspheres (divided into 3 groups of 10 each). The results are shown in Tables 1 and 2. Table 1. Statistical average values ​​of ferromagnetic resonance linewidths of NiZn single crystal microspheres before and after annealing in the examples.

[0033] Table 2. Statistical average values ​​of ferromagnetic resonance linewidths of NiZn single crystal microspheres before and after comparative annealing.

[0034] As can be seen from Tables 1 and 2, Examples 1 and 2 can effectively release the processing stress of the microspheres, reducing the ferromagnetic resonance linewidth of the NiZn single crystal microspheres by more than 30%. However, insufficient oxygen pressure during annealing (Comparative Example 1) makes it difficult to suppress the volatilization of Zn, rapid cooling (Comparative Example 2) causes the NiZn single crystal microspheres to accumulate thermal stress again, and annealing temperature that is too low (Comparative Example 3) is insufficient to eliminate processing stress, while annealing temperature that is too high (Comparative Example 4) will damage the crystal structure of the material, thus failing to achieve the desired improvement in the ferromagnetic resonance linewidth of the NiZn single crystal microspheres.

[0035] The above are the embodiments listed in this example. However, this example is not limited to the optional embodiments described above. Those skilled in the art can arbitrarily combine the above methods to obtain other various embodiments. Anyone can derive other various forms of embodiments based on the inspiration of this example. The above specific embodiments should not be construed as limiting the scope of protection of this example. The scope of protection of this example should be determined by the claims, and the specification can be used to interpret the claims.

Claims

1. A method for improving the ferromagnetic resonance linewidth of spinel NiZn ferrite single crystal microspheres, characterized in that: Includes the following steps: Spinel NiZn ferrite single crystal microspheres are annealed under high oxygen pressure and high temperature conditions, and then slowly cooled to room temperature. After annealing, the pressure is released to obtain the product.

2. The method for improving the ferromagnetic resonance linewidth of spinel NiZn ferrite single crystal microspheres according to claim 1, characterized in that: Under high oxygen pressure and high temperature conditions, the partial pressure of oxygen is PO2 = 6 MPa ~ 8 MPa.

3. The method for improving the ferromagnetic resonance linewidth of spinel NiZn ferrite single crystal microspheres according to claim 2, characterized in that: Under high oxygen pressure and high temperature conditions, the partial pressure of oxygen is PO2 = 6MPa, 7MPa or 8MPa.

4. The method for improving the ferromagnetic resonance linewidth of spinel NiZn ferrite single crystal microspheres according to claim 1, characterized in that: Under high oxygen pressure and high temperature conditions, the temperature is 800℃~1000℃ for 15h to 20h.

5. The method for improving the ferromagnetic resonance linewidth of spinel NiZn ferrite single crystal microspheres according to claim 1, characterized in that: The annealing cooling conditions are 10℃ / h to 20℃ / h.

6. The method for improving the ferromagnetic resonance linewidth of spinel NiZn ferrite single crystal microspheres according to claim 1, characterized in that: The rate of pressure release is 0.5 MPa to 1 MPa per minute.

7. The method for improving the ferromagnetic resonance linewidth of spinel NiZn ferrite single crystal microspheres according to claim 1, characterized in that: The spinel NiZn ferrite single crystal microspheres were placed in a platinum boat for annealing.

8. The method for improving the ferromagnetic resonance linewidth of spinel NiZn ferrite single crystal microspheres according to claim 7, characterized in that: The platinum boat is located in the central area of ​​the annealing furnace during early annealing.

9. The method for improving the ferromagnetic resonance linewidth of spinel NiZn ferrite single crystal microspheres according to claim 8, characterized in that: The annealing furnace is sealed during annealing.

10. A spinel NiZn ferrite single crystal microsphere, characterized in that: It was prepared using the treatment method for improving the ferromagnetic resonance linewidth of spinel NiZn ferrite single crystal microspheres as described in any one of claims 1-9.

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