Ka-band low linewidth gyromagnetic lithium-zinc ferrite and preparation method thereof

Abstract

The application discloses a Ka-band low-line-width gyromagnetic lithium-zinc ferrite and a preparation method thereof, and belongs to the technical field of microwave ferrite material preparation. 0.347 Zn 0.3 Ni 0.006 Mn 0.06 In x Fe 2.295‑x O4, x=0.005-0.03; based on the mass of the main material, the additives include: 0.8-1 wt% Bi2O3 and 0.1-0.3 wt% Sb2O3. The Ka-band low-line-width gyromagnetic lithium-zinc ferrite is prepared by using a two-step sintering method, that is, first sintering at 780-820 DEG C for 1-3 h, then passing oxygen, and then sintering at 1000-1050 DEG C for 2-4 h, so that the Ka-band low-line-width gyromagnetic lithium-zinc ferrite has low ferromagnetic resonance line width while keeping high saturation magnetization, high remanence ratio and low coercivity.

Description

Technical Field

[0001] This invention belongs to the field of microwave ferrite material preparation technology, specifically relating to a Ka-band low linewidth swirl moment lithium-zinc ferrite and its preparation method. Background Technology

[0002] In the 21st century, with the development of radar technology towards the millimeter-wave band, Ka-band radar, with its extremely high target resolution, excellent anti-jamming characteristics, and advantages in miniaturization and lightweighting, has become a key technology in modern high-precision detection and guidance. Ferrite phase shifters are typical microwave devices. During operation, the input signal receives a designable phase delay within the phase shift range, and the phase shift can be continuously or progressively adjusted through the magnetization state. Under the premise of meeting standing wave and loss constraints, these devices can typically provide a large phase shift range and maintain good phase repeatability and operational stability under high power conditions. For the core material of Ka-band phase shifters, LiZn ferrite is favored due to its high saturation magnetization (4πM). s ), high Curie temperature (T) c ), high remanence ratio (B r / B m With its advantages of high temperature stability and low manufacturing cost, ferrite has become the preferred material for high-performance phase shifters. Compared with semiconductor and microelectromechanical systems (MEMS) microwave devices, ferrite devices have significant advantages in high power capacity and low insertion loss. The high spin linewidth of ferrite materials guarantees high power capacity, while the low ferromagnetic resonance linewidth is a prerequisite for low insertion loss. Increasing the spin linewidth usually leads not only to an increase in ferromagnetic resonance linewidth but also to an increase in coercivity. Increasing the Curie temperature and remanence ratio also typically leads to an increase in the ferromagnetic resonance linewidth and coercivity of lithium ferrite. Therefore, how to reduce the ferromagnetic resonance linewidth and lower the coercivity while maintaining a high spin linewidth using appropriate substitution ions, additives, and manufacturing processes has become a critical issue that urgently needs to be addressed for high remanence lithium-based ferrite materials.

[0003] Traditional single-unit Li ferrites maintain a saturation magnetization of only around 3700 Gs, and the sintering process of single-unit Li ferrites is difficult to control. To achieve material densification, high sintering temperatures are typically required, which easily induces Li ion volatilization, leading to lattice defects. Lowering the sintering temperature can suppress Li volatilization, but it increases the internal porosity of the material. Porosity widening and magnetocrystalline anisotropy widening are the main sources of linewidth in polycrystalline ferrites. A high ferromagnetic resonance linewidth results in high insertion loss for the phase shifter, and high coercivity requires a large excitation current to achieve magnetic reversal, increasing the circuit load and limiting the overall system efficiency. Although the introduction of non-magnetic Ti can mitigate this issue... 4+ Ion-substituted Li + and Fe3+ The presence of ions effectively reduces the magnetocrystalline anisotropy field and ferromagnetic resonance linewidth, and also plays a certain role in sintering. However, this change in ion occupancy weakens the superexchange interaction between sublattices, inevitably leading to a decrease in the Curie temperature and saturation magnetization of the material. More importantly, Ti... 4+ Increased content often leads to a decrease in saturation magnetization, which directly weakens the phase shift per unit length of the phase shifter, hindering miniaturization and lightweight design. Therefore, developing a LiZn ferrite material that possesses both high saturation magnetization and excellent temperature stability, as well as low coercivity and low loss characteristics, is a key issue that needs to be addressed.

[0004] Regarding LiZn ferrite materials for phase shifters, relevant research reports have been published both domestically and internationally, mainly focusing on the main formulation, additives, and sintering process. For example, the patent with publication number CN109053180A, entitled "A Low-Temperature Sintering Low-Loss LiZn Ferrite Material and its Preparation Method," describes the preparation of LiZn ferrite materials using an oxide ceramic process. 0.43+x Zn 0.27 Ti 0.13-x-2y Bi x+y V y Fe 2.17 O4, 0.05≤x≤0.3, 0.05≤y≤0.15 ferrite, raw materials prepared according to stoichiometric ratio, and microwave ferrite material prepared using said raw materials, wherein the preferred embodiment has a dielectric constant of 15.5, 4πM s The value is 4335 Gs, ΔH is 159 Oe, and the coercivity H is... c =189A / m, remanence ratio B r / B m =0.88, but its line width is still too high and its coercivity is too large.

[0005] In summary, Ka-band microwave devices require low insertion loss. However, most existing research focuses on optimizing a single performance metric, either achieving a high remanence ratio but resulting in a high ferromagnetic resonance linewidth, leading to high device loss; or achieving a low ferromagnetic resonance linewidth but with a low remanence ratio, failing to meet the miniaturization requirements of Ka-band phase shifters. To date, there are few reports on fabrication techniques that can simultaneously maintain a high remanence ratio and achieve a low ferromagnetic resonance linewidth. Summary of the Invention

[0006] To address the technical problems existing in the prior art, the present invention provides a Ka-band low linewidth gyroscope lithium-zinc ferrite and its preparation method. Through specific formulations, additives and preparation processes, the material obtained maintains high saturation magnetization, high remanence ratio and low coercivity while also having low ferromagnetic resonance linewidth.

[0007] The technical solution adopted in this invention is as follows:

[0008] A Ka-band low linewidth gyroscope lithium-zinc ferrite comprises a main material and additives, wherein the main material is Li 0.347 Zn 0.3 Ni 0.006 Mn 0.06 In x Fe 2.295-x O4, where x = 0.005~0.03; based on the mass of the main material, the additives include: 0.8~1wt% Bi2O3, 0.1~0.3wt% Sb2O3.

[0009] A method for preparing Ka-band low linewidth gyrometric moment lithium-zinc ferrite includes the following steps:

[0010] Step 1: Using Li₂CO₃, NiO, ZnO, Mn₃O₄, In₂O₃, and Fe₂O₃ as raw materials, according to the molecular formula Li 0.347 Zn 0.3 Ni 0.006 Mn 0.06 In x Fe 2.295-x O4 is used to calculate and weigh the raw materials, where x = 0.005~0.03;

[0011] Step 2: Mix all the raw materials weighed in Step 1, ball mill them once to obtain the ball milled material, place it in a muffle furnace, heat it to 770~830℃ and pre-calcine it for 2~3 hours, and then cool it to obtain the pre-calcined material;

[0012] Step 3: Based on the mass of the pre-fired material obtained in Step 2, add 0.8~1 wt% Bi2O3 and 0.1~0.3 wt% Sb2O3 to the pre-fired material to obtain mixed powder. After secondary ball milling and sieving, obtain secondary ball milled material.

[0013] Step 4: Granulate the secondary ball milling material into green blanks, place them in an oxygen atmosphere furnace for two-step sintering. Specifically, first heat the furnace to 780~820℃ and sinter for 1~3 hours, then introduce oxygen, and then heat the furnace to 1000~1050℃ and sinter for 2~4 hours. After cooling, the Ka-band low linewidth helical torque lithium zinc ferrite is obtained.

[0014] Furthermore, the D of the secondary ball milling material sieved in step 3 50 The particle size is 1.2~1.8 μm.

[0015] Furthermore, the heating rate in step 2 is 1~1.2℃ / min.

[0016] Furthermore, in step 4, the first heating rate is 0.5~1℃ / min, and the second heating rate is 0.2~0.5℃ / min.

[0017] Furthermore, in step 4, the partial pressure of oxygen is 0.1~0.3 MPa.

[0018] Further, step 4 involves granulation by adding a binder to the secondary ball milling material.

[0019] Furthermore, the adhesive is polyvinyl alcohol (PVA) colloid, and the amount of adhesive added is 8-12 wt% of the secondary ball milling material.

[0020] Furthermore, the particle size of the granulation in step 4 is 106~180 μm.

[0021] Furthermore, the density of the green blank in step 4 is 2.6~3 g / cm³. 3 .

[0022] The technical specifications of the Ka-band low linewidth swirl moment lithium-zinc ferrite proposed in this invention are as follows:

[0023] Saturation magnetization 4πM s 4800±5% Gs;

[0024] Coercivity H c ≤1.25Oe;

[0025] Curie temperature T c ≥430℃;

[0026] Remanence ratio B r / B m ≥0.88;

[0027] Ferromagnetic resonance linewidth ΔH: ≤100Oe;

[0028] Dielectric constant ε′:=15±10%;

[0029] Dielectric loss tanδ ε ≤5.5×10 -4 ;

[0030] Temperature coefficient of remanence α Br ≤1.8×10 -3 / ℃ (-25℃~+125℃).

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] 1. This invention proposes a Ka-band low linewidth helical torque lithium-zinc ferrite and its preparation method. By optimizing the main formulation system, it helps to reduce the ferromagnetic resonance linewidth and obtain low-loss and low-coercivity Ka-band ferrite switches and phase shifters lithium-zinc ferrite materials to meet the application requirements of Ka-band low-loss ferrite phase shifters and switches.

[0033] 2. Specifically, the present invention is based on Li 0.5 Fe 2.5 On the main body of the O4 formulation, non-magnetic In is used. 3+ Ion-substituted Fe 3+ To regulate the occupancy of metal ions in ferrites in order to reduce the magnetocrystalline anisotropy constant of ferrites, the main influencing factors on the ferromagnetic resonance linewidth of the material are magnetocrystalline anisotropy and porosity. Non-magnetic In... 3+ It can reduce the magnetocrystalline anisotropy of the material, thereby reducing the ferromagnetic resonance linewidth; introducing Mn into the formulation 3+ To reduce the dielectric loss of the material; using a small amount of Ni 2+ Ion substitution gives the material a high remanence ratio and low coercivity; at the same time, the use of an iron-deficient formulation reduces the amount of Fe generated during sintering. 2+ Ions further reduce the dielectric loss of the material;

[0034] 3. Regarding additives, this invention utilizes the combined effect of Bi2O3 and Sb2O3 additives to compensate for the sintering non-density problem caused by the low Li content due to high saturation magnetization, and achieves densification sintering at a lower temperature, reducing lattice defects caused by lithium volatilization. At the same time, it controls porosity and grain / grain boundary characteristics by optimizing the sintering process, thereby reducing the ferromagnetic resonance linewidth.

[0035] 4. The Ka-band low linewidth gyroscope lithium-zinc ferrite obtained by this invention can simultaneously maintain high saturation magnetization, high remanence ratio, low ferromagnetic resonance linewidth, and low coercivity. Attached Figure Description

[0036] Figure 1 The image shows a scanning electron microscope (SEM) image of the surface of the Ka-band low linewidth gyroscope lithium-zinc ferrite obtained in Example 1.

[0037] Figure 2 The image shows a scanning electron microscope (SEM) image of the surface of the Ka-band low linewidth gyroscope lithium-zinc ferrite obtained in Example 2.

[0038] Figure 3 The image shows a scanning electron microscope (SEM) image of the surface of the Ka-band low linewidth gyroscope lithium-zinc ferrite obtained in Example 3.

[0039] Figure 4 The image shows the hysteresis loop of the Ka-band low linewidth gyrotor lithium-zinc ferrite obtained in Example 1. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0041] The purity of the raw materials used in the following examples and comparative examples is as follows: Li2CO3 purity is 99.0%, NiO purity is 99.0%, TiO2 purity is 99.0%, ZnO purity is 99.7%, Mn3O4 purity is 99.0%, Fe2O3 purity is 99.3%, Bi2O3 purity is 99.0%, and Sb2O3 purity is 99.9%.

[0042] Example 1

[0043] This embodiment prepares a Ka-band low-linewidth helical-moment lithium-zinc ferrite, specifically including the following steps:

[0044] Step 1, Ingredients:

[0045] Using Li₂CO₃, NiO, In₂O₃, ZnO, Mn₃O₄, and Fe₂O₃ as raw materials, according to the molecular formula Li 0.347 Zn 0.3 Ni 0.006 Mn 0.06 In 0.01 Fe 2.285 Calculate O4 and weigh the raw materials;

[0046] Step 2, First ball milling:

[0047] All the raw materials weighed in step 1 were ball-milled once in a planetary ball mill by wet ball milling for 2 hours. Deionized water was used as the ball milling medium. The diameter of the zirconia balls was 3~6 mm. The mass ratio of raw materials: ball milling medium: zirconia balls was 1:1.5:3. After ball milling, the raw materials were dried and passed through a 40-mesh sieve to obtain the primary ball milling material.

[0048] Step 3, Preheating:

[0049] The ball milling material obtained in step 2 was placed in an alumina pre-calcined crucible and placed in a muffle furnace. The temperature was increased to 800℃ at a rate of 1.2℃ / min and held for 3 hours. After the process, the material was allowed to cool naturally to room temperature in the furnace to obtain the pre-calcined material.

[0050] Step 4, Secondary ball milling:

[0051] Using the mass of the pre-calcined material obtained in step 3 as a baseline, 1 wt% Bi₂O₃ and 0.1 wt% Sb₂O₃ were added as additives to the pre-calcined material to obtain a mixed powder. The resulting mixed powder was then subjected to a second ball milling process in a planetary ball mill using wet ball milling for 6 hours. Deionized water was used as the grinding media, and the mass ratio of mixed powder: grinding media: zirconia balls was 1:1.5:3. After ball milling, the powder was dried and passed through a 40-mesh sieve to obtain the secondary ball-milled material, D. 50 The particle size is 1.2~1.8 μm;

[0052] Step 5: Granulation and molding:

[0053] In step 4, 12 wt% PVA colloid was added as a binder to the secondary ball milling material, and granulation was performed. The particle size of the granulated material was controlled at 106~180 μm. The granulated material was placed in a mold and pressed into a ring-shaped green body under 8 MPa. The green body density was 2.9 g / cm³. 3 ;

[0054] Step 6, Sintering:

[0055] The annular green blank obtained in step 5 was placed in an oxygen atmosphere furnace and sintered using a two-step sintering method. First, it was sintered at 780℃ for 2 hours with a heating rate of 0.5℃ / min and oxygen was introduced at a partial pressure of 0.2 MPa. Then, it was sintered at 1030℃ for 2 hours with a heating rate of 0.3℃ / min. After sintering, it was cooled to room temperature with the furnace to obtain the Ka-band low linewidth gyroscope lithium zinc ferrite.

[0056] Example 2

[0057] This embodiment prepares a Ka-band low-linewidth helical-moment lithium-zinc ferrite, specifically including the following steps:

[0058] Step 1, Ingredients:

[0059] Using Li₂CO₃, NiO, In₂O₃, ZnO, Mn₃O₄, and Fe₂O₃ as raw materials, according to the molecular formula Li 0.347 Zn 0.3 Ni 0.006 Mn 0.06 In 0.03 Fe 2.265 Calculate O4 and weigh the raw materials;

[0060] Step 2, First ball milling:

[0061] All the raw materials weighed in step 1 were ball-milled once in a planetary ball mill by wet ball milling for 2 hours. Deionized water was used as the ball milling medium. The diameter of the zirconia balls was 3~6 mm. The mass ratio of raw materials: ball milling medium: zirconia balls was 1:1.5:3. After ball milling, the raw materials were dried and passed through a 40-mesh sieve to obtain the primary ball milling material.

[0062] Step 3, Preheating:

[0063] The ball milling material obtained in step 2 was placed in an alumina pre-calcined crucible and placed in a muffle furnace. The temperature was increased to 800°C at a rate of 1°C / min and held for 2 hours. After the process, the material was allowed to cool naturally to room temperature in the furnace to obtain the pre-calcined material.

[0064] Step 4, Secondary ball milling:

[0065] Using the mass of the pre-calcined material obtained in step 3 as a baseline, 1 wt% Bi₂O₃ and 0.3 wt% Sb₂O₃ were added as additives to the pre-calcined material to obtain a mixed powder. The resulting mixed powder was then subjected to a second ball milling process in a planetary ball mill using wet ball milling for 6 hours. Deionized water was used as the grinding media, and the mass ratio of mixed powder: grinding media: zirconia balls was 1:1.5:3. After ball milling, the powder was dried and passed through a 40-mesh sieve to obtain the secondary ball-milled material, D. 50 The particle size is 1.2~1.8 μm;

[0066] Step 5: Granulation and molding:

[0067] In step 4, 12 wt% PVA colloid was added as a binder to the secondary ball milling material, and granulation was performed. The particle size of the granulated material was controlled at 108~180 μm. The granulated material was placed in a mold and pressed into a ring-shaped green body under 8 MPa. The green body density was 2.9 g / cm³. 3 ;

[0068] Step 6, Sintering:

[0069] The annular green blank obtained in step 5 was placed in an oxygen atmosphere furnace and sintered using a two-step sintering method. First, it was sintered at 780℃ for 2 h with a heating rate of 0.6℃ / min, and oxygen was introduced with an oxygen partial pressure of 0.2 MPa. Then, it was sintered at 1030℃ for 2 h with a heating rate of 0.4℃ / min. After sintering, it was cooled to room temperature with the furnace to obtain the Ka-band low linewidth gyroscope lithium zinc ferrite.

[0070] Example 3

[0071] This embodiment prepares a Ka-band low linewidth gyroscope lithium-zinc ferrite. The preparation process is the same as that in Example 1, except that the additives added in step 4 are adjusted to "1 wt% Bi2O3, 0.15 wt% Sb2O3"; the other steps remain unchanged.

[0072] Comparative Example 1

[0073] This comparative example prepared a lithium-zinc ferrite, specifically including the following steps:

[0074] Step 1, Ingredients:

[0075] Using Li₂CO₃, NiO, ZnO, Mn₃O₄, and Fe₂O₃ as raw materials, according to the molecular formula Li 0.347 Zn 0.3 Ni 0.006 Mn 0.06 Fe 2.295Calculate O4 and weigh the raw materials;

[0076] Step 2, First ball milling:

[0077] All the raw materials weighed in step 1 were ball-milled once in a planetary ball mill by wet ball milling for 2 hours. Deionized water was used as the ball milling medium. The diameter of the zirconia balls was 3~6 mm. The mass ratio of raw materials: ball milling medium: zirconia balls was 1:1.5:3. After ball milling, the raw materials were dried and passed through a 40-mesh sieve to obtain the primary ball milling material.

[0078] Step 3, Preheating:

[0079] The ball milling material obtained in step 2 was placed in an alumina pre-calcined crucible and placed in a muffle furnace. The temperature was increased to 800°C at a rate of 1°C / min and held for 3 hours. After the process, the material was allowed to cool naturally to room temperature in the furnace to obtain the pre-calcined material.

[0080] Step 4, Secondary ball milling:

[0081] Using the mass of the pre-calcined material obtained in step 3 as a baseline, 1 wt% Bi₂O₃ and 0.1 wt% Sb₂O₃ were added as additives to the pre-calcined material to obtain a mixed powder. The resulting mixed powder was then subjected to a second ball milling process in a planetary ball mill using wet ball milling for 6 hours. Deionized water was used as the grinding media, and the mass ratio of mixed powder: grinding media: zirconia balls was 1:1.5:3. After ball milling, the powder was dried and passed through a 40-mesh sieve to obtain the secondary ball-milled material, D. 50 The particle size is 1.2~1.8 μm;

[0082] Step 5: Granulation and molding:

[0083] In step 4, 12 wt% PVA colloid was added as a binder to the secondary ball milling material, and granulation was performed. The particle size of the granulated material was controlled at 108~180 μm. The granulated material was placed in a mold and pressed into a ring-shaped green body under 8 MPa. The green body density was 2.9 g / cm³. 3 ;

[0084] Step 6, Sintering:

[0085] The annular green blank obtained in step 5 was placed in an oxygen atmosphere furnace and sintered using a two-step sintering method. First, it was sintered at 770℃ for 2 hours with a heating rate of 0.5℃ / min, and then sintered at 1010℃ for 2 hours with a heating rate of 0.8℃ / min. After sintering, it was cooled to room temperature with the furnace to obtain the lithium zinc ferrite.

[0086] The microstructure of the low-linewidth, gyrometric lithium-zinc ferrites obtained in Examples 1-3 was characterized using scanning electron microscopy (SEM), and the results are as follows: Figures 1-3 As shown in the microstructure diagram, after the introduction of In, the surface morphology of lithium zinc ferrite is relatively dense, the grain size is uniform and moderate, and the porosity is low. This is beneficial to improving the power handling capacity and sintered body density of the material, and reducing the ferromagnetic resonance linewidth of the material.

[0087] The magnetic properties of the low linewidth helical moment lithium-zinc ferrites obtained in Examples 1-3 and the lithium-zinc ferrite obtained in Comparative Example 1 were tested using a vibrating sample magnetometer (VSM) and other testing equipment. These tests included measurements of the saturation magnetization of 4πM. s Remanence ratio B r / B m Coercivity H c Ferromagnetic resonance linewidth ΔH*, dielectric constant ε′*, dielectric loss tanδ ε * and remanence temperature coefficient α Br The results are shown in Table 1 below, where the parameter marked with * has a test frequency of f = 9.3 GHz.

[0088] Table 1

[0089]

[0090] Based on the magnetic property test results in Table 1, it can be seen that: Examples 1-3 in non-magnetic In 3+ Ion-substituted Fe 3+ Subsequently, the ferromagnetic resonance linewidth ΔH* of the lithium-zinc ferrite was significantly reduced, the saturation magnetization 4πMs was improved, and the coercivity H was increased. c The remanence ratio Br / Bm is reduced to a certain extent, which, combined with the maintained high remanence ratio, makes it more suitable for the application requirements of Ka-band latch-up phase shifters, and is conducive to promoting the development of Ka-band phase shifters towards miniaturization and low loss.

[0091] Figure 4 The image shows the hysteresis loop of the Ka-band low linewidth helical moment lithium-zinc ferrite obtained in Example 1. The BH loop shows that the material has a high remanence ratio, which meets the application requirements of miniaturized latch-up phase shifters.

[0092] It should be noted that this is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A Ka-band low linewidth gyroscope-moment lithium-zinc ferrite, characterized in that, It includes the main ingredient and additives, wherein the main ingredient is Li 0.347 Zn 0.3 Ni 0.006 Mn 0.06 In x Fe 2.295-x O4, where x = 0.005~0.03; based on the mass of the main material, the additives include: 0.8~1 wt% Bi2O3, 0.1~0.3 wt% Sb2O3.

2. A method for preparing a Ka-band low linewidth gyroscope lithium-zinc ferrite, characterized in that, Includes the following steps: Step 1: Using Li₂CO₃, NiO, ZnO, Mn₃O₄, In₂O₃, and Fe₂O₃ as raw materials, according to the molecular formula Li 0.347 Zn 0.3 Ni 0.006 Mn 0.06 In x Fe 2.295-x O4 is used to calculate and weigh the raw materials, where x = 0.005~0.03; Step 2: Mix all the raw materials weighed in Step 1, ball mill them once to obtain the ball milled material, place it in a muffle furnace, heat it to 770~830℃ and pre-fire it for 2~3 hours, then cool it to obtain the pre-fired material; Step 3: Based on the mass of the pre-fired material obtained in Step 2, add 0.8~1 wt% Bi2O3 and 0.1~0.3 wt% Sb2O3 to the pre-fired material to obtain mixed powder. After secondary ball milling and sieving, obtain secondary ball milled material. Step 4: Granulate the secondary ball milling material into green blanks and place them in an oxygen atmosphere furnace for two-step sintering. Specifically, first heat the furnace to 780~820℃ and sinter for 1~3 hours, then introduce oxygen, and then heat the furnace to 1000~1050℃ and sinter for 2~4 hours. After cooling, Ka-band low linewidth gyroscope lithium zinc ferrite is obtained.

3. The Ka-band low linewidth helical moment lithium-zinc ferrite according to claim 2, characterized in that, D of the secondary ball milling material sieved in step 3 50 The particle size is 1.2~1.8 μm.

4. The Ka-band low linewidth helical moment lithium-zinc ferrite according to claim 2, characterized in that, The heating rate in step 2 is 1~1.2℃ / min.

5. The Ka-band low linewidth helical moment lithium-zinc ferrite according to claim 2, characterized in that, In step 4, the first heating rate is 0.5~1℃ / min, and the second heating rate is 0.2~0.5℃ / min.

6. The Ka-band low linewidth helical moment lithium-zinc ferrite according to claim 2, characterized in that, In step 4, the partial pressure of oxygen is 0.1~0.3 MPa.

7. The Ka-band low linewidth helical moment lithium-zinc ferrite according to claim 2, characterized in that, Step 4 involves granulation by adding a binder to the secondary ball milling material.

8. The Ka-band low linewidth helical moment lithium-zinc ferrite according to claim 7, characterized in that, In step 4, the particle size of the granulation is 106~180 μm.

9. The Ka-band low linewidth helical moment lithium-zinc ferrite according to claim 8, characterized in that, The density of the green blank in step 4 is 2.6~3 g / cm³. 3 .

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