易面各向异性磁粉复合材料微波吸收性能的研究
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摘要
近年来,电磁器件被广泛应用于军事民用设备(雷达,无线电通讯技术,局域网系统,个人电子记事簿等)。目前,其应用频率已经到达了GHz,随着高频电磁器件的应用日益广泛,电磁干扰作为一种新的特殊的环境污染已经受到了越来越多的关注,因此,研发电磁波吸收材料已成为当务之急。无论是电磁屏蔽还是抗电磁干扰,都要求吸波体具有“薄,轻,宽,强”即：“厚度薄,质量轻,吸收频带宽,吸波性能强”的特点。基于四分之一波长模型及阻抗匹配理论,对于金属磁粉吸波体,高的复数磁导率及适中的介电常数是满足上面要求的必要条件。依据双各向异性模型,具有易面各向异性的材料可以突破Snoek极限的限制,使得样品在微波段获得高的复数磁导率,有望成为新一代吸波体的设计理念。
在上述理论模型的指导下,我们从实验上制备了具有易面形状各向异性的羰基铁微粉以及具有易面磁晶各向异性的稀土-3d过渡族金属间化合物。研究了易面各向异性材料的高频磁电特性及微波吸收性能,并对它们的微波吸收机理(吸收峰值频率与吸波体厚度及相应电磁参数的关系,前后界面反射能量对吸波体吸波性能的影响)进行了探讨。依照前后界面反射能量对吸波体吸波性能的影响,我们对实验进行了改进并获得了优异的微波吸收性能。研究的主要内容和结果如下：
1.材料的选择。为了获得良好的高频磁性,材料的选择至关重要,对于不同型号的羰基铁微粉由于制备工艺的不同,材料的成分,硬度及颗粒尺寸存在很大差异,即使在相同的处理条件下,得到的样品形貌、静态磁性以及高频磁性会存在很大的差异。将尺寸相近的球形羰基铁原粉RXEL和RXEG在相同球磨速度(400r/min)下球磨12h。球磨后,RXEL样品基本呈片状,而RXEG样品呈现不规则颗粒形状。由于RXEL羰基铁呈片状,并且厚度低于样品的趋肤深度,因此在2GHz以前,微粉/石蜡复合材料的磁导率实部基本为常数,不随频率变化,而RXEG微粉/石蜡复合材料的复数磁导率实部随频率的增大迅速下降；
2.易面各向异性羰基铁粉最佳制备条件。分别从球磨时间及球磨速度两个方面对易面性羰基铁的制备进行了研究。球磨时间：将球形羰基铁微粉在固定速度下分别球磨8h,12h和16h。球磨后,样品基本呈片状,当球磨时间为16h时,样品出现冷焊接。随球磨时间的增大,磁导率实部初始值(0.1GHz)降低,共振频率向低频方向移动。因此,我们选择最佳球磨时间为8h。其后,在固定8h球磨时间下,改变球磨速度分别为200r/min,350r/min,400r/min,450r/min,500r/min,550r/min。样品的磁导率实部初始值随球磨速度的增大先增大后减小,与样品饱和磁化强度变化规律一致,在比较了样品的磁导率初始值及样品的共振频率后,我们选择最佳球磨速度为500r/min;
3.为了优化样品的高频磁性和微波吸收性能,我们对样品进行了磁场旋转取向,取向后样品的磁导率实部初始值(0.1GHz)较未取向样品有0.2-0.3倍的提高,共振频率向高频方向移动。取向后样品的介电常数升高。从而使样品/石蜡复合材料的最佳匹配厚度降低,最佳匹配频率向低频方向移动。
4.为了降低片状样品高的复数介电常数,改善样品的阻抗匹配,我们用Stober方法在易面型羰基铁颗粒表面包覆了一层非晶二氧化硅层。包覆后,易面型羰基铁@二氧化硅核壳磁粉/石蜡复合材料的复数磁导率微弱降低,而介电常数则明显降低,从而提高了复合材料的阻抗匹配和微波吸收性能。分别研究了在不同体积比无水乙醇/水溶液以及正硅酸乙脂和氨水的投入量对包覆结果的影响,确定了最佳包覆条件。
5.为了在准微波频段(1-4GHz)得到薄的微波吸收体,通过化学共沉淀的方法,在易面型羰基铁颗粒表面生长了一层致密的ZnO纳米颗粒壳层。相对于未包覆的球磨微粉由于半导体ZnO壳层的作用,易面型羰基铁@ZnO核壳磁粉/石蜡复合材料(vol.35%)的复数介电常数大大降低,提高了阻抗匹配特性及微波吸收性能。在2.5mm匹配厚度下,其最佳吸收在1.96GHz时达到了-31.9dB。
6.通过水热法成功制备了易面型羰基铁＠Ni0.5Zn0.5Fe2O4核壳磁粉作为微波吸收材料。通过LLG方程及有效介质理论计算了样品复数磁导率随频率的变化关系,从而证明了样品的磁损主要来自于自然共振。相对于未包覆的易面型羰基铁微粉包覆铁氧体纳米壳层,在降低易面型羰基铁介电常数的前提下,有效地控制了复数磁导率的降低,在准微波频段(1-4GHz)获得了优异的微波吸收性能；
7.通过熔炼及高温煅烧淬火的方法制备了一种新型的具有易面各向异性的Ce2Fe17N3－δ微粉,研究了不同磁场大小取向对样品复数磁导率的影响。定义并通过XRD方法测量了不同磁场大小取向复合材料的取向度。在1.6T磁场下取向样品的取向度为62.4%,磁导率实部值在2GHz时为4.8。
8.通过快淬方法制备纳米晶Sm2Fe14B微粉,研究了不同体积百分含量微粉／石蜡复合材料复数磁导率及复数介电常数随频率的变化。对于体积浓度为50%的样品,在最佳匹配频率点,样品的复数介电常数与复数磁导率的比值远大于1,与传统的在最佳匹配频率点复数介电常数等于复数磁导率的观点不同。复合材料在相对自由空间阻抗(Zin/Zo)为1时,出现了最佳匹配频率点(2.9GHz),反射吸收最小值达到了-42.0dB。
9.利用界面反射模型,解释了反射吸收峰出现的位置及强度。证明了界面反射对微波吸收性能的巨大影响,即使在完全吸收的条件下,电磁损耗所消耗的能量也只占了一小部分；
10.通过前界面涂覆,改变了样品反射回自由空间的能量,增强了样品微波吸收性能,近一步验证了界面反射模型的正确性。
Recently, electromagnetic (EM) wave devices have been widely used in both military and civil applications:radar, wireless communication tools, local area net works, personal digital assistant, etc. The frequency of EM wave has reached gigahertz (GHz) range. However, the increasing usage of EM waves in the GHz electromagnetic interference (EMI) and electromagnetic compatibility (EMC) problems which have drawn more attention as a specific kind of environmental pollution. To solve this problem, it is necessary to exploit a type of microwave absorption materials with thinner thickness, lighter weight, wider frequency band of microwave loss and more intensity of the microwave sbsorption. Complex permittivity and permeability of the absorbers play key roles in determining the absorption properties. According to the quarter-wavelength model, for metal magnetic absorbers, higher permeability and appropriate permittivity values are needed to satisfy the above demands. According to the bianisotropy theory, the easy-plane anisotropy materials can exceed the limit of the Snoek's limit and obtain a higher permeability in higher frequency range.
The shape planar anisotropy carbonyl-iron powder and magnetocrystalline easy-plane anisotropy rare-earth3d transition intermetallics have been prepared based on the bianisotropy theory. The dependence of the complex permeability, permittivity and the microwave absorption properties of these materials were investigated. On the other hand, we discussed the relation between the frequency of microwave loss, the thickness of the absorber and the complex permeability and permittivity. Moreover, the reflection of the reflective wave by the absorber and the perfect conductor to the microwave absorption properties was also investigated. According to the reflective loss model, we further improved the microwave absorption properties of the absorbers. The details and results of our research are listed as follows:
1. The choice of the easy-plane anisotropy materials. The morphology, static magnetic properties and high frequency properties of the ball milling particles will be different even in the same ball milling method, due to the different types of carbonyl-iron particles have different surface treatment. The RXEG and RXEL sphere-shaped carbonyl-iron particles were ball milling with400r/min for12hours. The ball milled RXEG particles have irregular shape, while the ball milled RXEL particles is flake-shaped. The thickness of the ball milled RXEL particles is lower than the skin depth of the iron particles, which induces that the permeability of the particles is almost constant up to2GHz. On the other hand, the permeability of the ball milling RXEG particles decreased rapidly with the increasing frequency.
2. To optimize the ball milling method. The RXEL sphere-shaped carbonyl-iron particles were ball milled under400r/min for8hs,12hs and16hs. The raw powders are deformed into thin flake particles after ball milling, and the flaky appears cold welding state for16hs ball milled particles. The permeability of the particles decreases and the resonance frequency shifts to lower frequency with increasing ball milling time. When ball milling time is used as8hs, the product of the permeability and the resonance frequency can maximum exceed the Snoek's limit. Then, the raw particles were ball milled under different speeds (200r/min,350r/min,400r/min,450r/min,500r/min,550r/min.) for8hs. The permeability of the samples are first increase and then decreased with increasing the ball milling speeds, which is consist with the change of the morphology and static magnetic properties. In summary, the raw particles are ball milled under500r/min for8hs possess a best frequency property.
3. In order to further optimize the high frequency properties and the microwave absorption properties of the easy-plane anisotropy canbonyl-iron particles. The easy-plane anisotropy canbonyl-iron/paraffin composite was oriented in an external magnetic field. The permeability of composite has an increasing factor of0.2-0.3than the nonoriented one. The resonance frequency and the permittivity of the oriented composite increase compared with the nonoriented one, and thus the matching thickness and the matching frequency decrease for the oriented composite.
4. To reduce the permittivity of the easy-plane anisotropy carbonyl-iron particles, the surface of the particles were coated with a thin layer of amorphous SiO2by Stober method. After coating SiO2layer, the permittivity of the easy-plane anisotropy carbonyl-iron/SiO2decreases significantly while the permeability shows a small decrease, which increase the threshold value of the volume fractions. By change the volume rate of the absolute ethyl alcohol/the water, the amount of the TEOS and the ammonia, the optimized condition of coating SiO2layer are obtained.
5. For the aim of thin electromagnetic wave absorbers used in quasimicrowave frequency band, easy-plane anisotropy carbonyl-iron (PACI) particles coated with ZnO nanoshells were prepared by ball milling technique and chemical precipitation method. Compared with the as-milled PACI/paraffin composite, lower electric constant was obtained for the composite containing PACI at ZnO particles, and hence a dramatic enhancement of reflection loss (RL) was obtained. The minimum RL of PACI at ZnO composite reaches-31.93dB at1.96GHz with the matching thickness of2.5mm. The PACI at ZnO core-shell particles exhibit great potential in application of the thin absorber in the1-4GHz frequency range.
6. easy-plane anisotropy carbonyl-iron (PACI)/Nio.5Zno.5Fe204composite as absorbent filler in quasimicrowave band has been synthesized via ball-milling technique and solvothermal method. The effective permeability of the composite was measured and calculated. The result indicates that the magnetic loss in the composite is mainly caused by the natural resonance. Compared with the uncoated PACI particles, the permittivity of the composite decreased dramatically, and hence a dramatic enhancement of reflection loss (RL) was obtained in quasimicrowave band. This result indicates that our PACI/ferrite composite can be used as potential microwave absorbers in quasimicrowave band for its novel microwave properties.
7. A new easy-plane anisotropy Ce2Fe17N3-δ compound as an electromagnetic absorption material was prepared by arc melting method. The influence of rotational orientation in various magnetic fields on the complex permeability and orientation degrees of the compound/paraffin composites were systematically studied. It is found that the orientation plays an important role in complex permeability and orientation degrees. For the composite with rotational orientation in1.6T, the real permeability reaches a large value of4.8at2GHz and the imaginary part reaches2.6at5.5GHz, on the other hand, the orientation degree reaches62.4%. It is evident that the oriented Ce2Fe17N3-δ composite with easy-plane anisotropy may have potential applications as microwave absorption materials.
8. A new easy-plane anisotropy Sm2Fe14B nanocrystal as an electromagnetic absorption material was prepared by melt spinning method. The electromagnetic and microwave absorbing properties of Sm2Fe14B nanocrystal/nonmagnetic matrix composite in the frequency range of0.1-10GHz were measured and calculated. At the perfect matching point (2.9GHz, vol.50%); the minimum reflection loss reaches-42.0dB at the matching thickness of3.1mm. Furthermore, the calculation shows that the normalized input impedance Zin/Zo equals to1, but the modulus of the ratio between the complex permittivity and permeability|ε/μ|is far away from unity at the perfect matching point.
9. The matching frequency and the intensity of reflection loss for the absorbers obey the quarter-wavelength model and the reflective loss model. The results show that the peak intensity of the RL is directly affected by the intensity of the reflective wave from the absorber layer and the emerging wave from the metal layer. The intensity of these two reflective waves dominates the intensity of the reflection loss even at the perfect matching point.
10. Coating a conductor layer in the front layer of the absorber can change the intensity of the reflective wave from the absorber layer interface and improve the microwave absorption properties of the absorbers.
在上述理论模型的指导下,我们从实验上制备了具有易面形状各向异性的羰基铁微粉以及具有易面磁晶各向异性的稀土-3d过渡族金属间化合物。研究了易面各向异性材料的高频磁电特性及微波吸收性能,并对它们的微波吸收机理(吸收峰值频率与吸波体厚度及相应电磁参数的关系,前后界面反射能量对吸波体吸波性能的影响)进行了探讨。依照前后界面反射能量对吸波体吸波性能的影响,我们对实验进行了改进并获得了优异的微波吸收性能。研究的主要内容和结果如下：
1.材料的选择。为了获得良好的高频磁性,材料的选择至关重要,对于不同型号的羰基铁微粉由于制备工艺的不同,材料的成分,硬度及颗粒尺寸存在很大差异,即使在相同的处理条件下,得到的样品形貌、静态磁性以及高频磁性会存在很大的差异。将尺寸相近的球形羰基铁原粉RXEL和RXEG在相同球磨速度(400r/min)下球磨12h。球磨后,RXEL样品基本呈片状,而RXEG样品呈现不规则颗粒形状。由于RXEL羰基铁呈片状,并且厚度低于样品的趋肤深度,因此在2GHz以前,微粉/石蜡复合材料的磁导率实部基本为常数,不随频率变化,而RXEG微粉/石蜡复合材料的复数磁导率实部随频率的增大迅速下降；
2.易面各向异性羰基铁粉最佳制备条件。分别从球磨时间及球磨速度两个方面对易面性羰基铁的制备进行了研究。球磨时间：将球形羰基铁微粉在固定速度下分别球磨8h,12h和16h。球磨后,样品基本呈片状,当球磨时间为16h时,样品出现冷焊接。随球磨时间的增大,磁导率实部初始值(0.1GHz)降低,共振频率向低频方向移动。因此,我们选择最佳球磨时间为8h。其后,在固定8h球磨时间下,改变球磨速度分别为200r/min,350r/min,400r/min,450r/min,500r/min,550r/min。样品的磁导率实部初始值随球磨速度的增大先增大后减小,与样品饱和磁化强度变化规律一致,在比较了样品的磁导率初始值及样品的共振频率后,我们选择最佳球磨速度为500r/min;
3.为了优化样品的高频磁性和微波吸收性能,我们对样品进行了磁场旋转取向,取向后样品的磁导率实部初始值(0.1GHz)较未取向样品有0.2-0.3倍的提高,共振频率向高频方向移动。取向后样品的介电常数升高。从而使样品/石蜡复合材料的最佳匹配厚度降低,最佳匹配频率向低频方向移动。
4.为了降低片状样品高的复数介电常数,改善样品的阻抗匹配,我们用Stober方法在易面型羰基铁颗粒表面包覆了一层非晶二氧化硅层。包覆后,易面型羰基铁@二氧化硅核壳磁粉/石蜡复合材料的复数磁导率微弱降低,而介电常数则明显降低,从而提高了复合材料的阻抗匹配和微波吸收性能。分别研究了在不同体积比无水乙醇/水溶液以及正硅酸乙脂和氨水的投入量对包覆结果的影响,确定了最佳包覆条件。
5.为了在准微波频段(1-4GHz)得到薄的微波吸收体,通过化学共沉淀的方法,在易面型羰基铁颗粒表面生长了一层致密的ZnO纳米颗粒壳层。相对于未包覆的球磨微粉由于半导体ZnO壳层的作用,易面型羰基铁@ZnO核壳磁粉/石蜡复合材料(vol.35%)的复数介电常数大大降低,提高了阻抗匹配特性及微波吸收性能。在2.5mm匹配厚度下,其最佳吸收在1.96GHz时达到了-31.9dB。
6.通过水热法成功制备了易面型羰基铁＠Ni0.5Zn0.5Fe2O4核壳磁粉作为微波吸收材料。通过LLG方程及有效介质理论计算了样品复数磁导率随频率的变化关系,从而证明了样品的磁损主要来自于自然共振。相对于未包覆的易面型羰基铁微粉包覆铁氧体纳米壳层,在降低易面型羰基铁介电常数的前提下,有效地控制了复数磁导率的降低,在准微波频段(1-4GHz)获得了优异的微波吸收性能；
7.通过熔炼及高温煅烧淬火的方法制备了一种新型的具有易面各向异性的Ce2Fe17N3－δ微粉,研究了不同磁场大小取向对样品复数磁导率的影响。定义并通过XRD方法测量了不同磁场大小取向复合材料的取向度。在1.6T磁场下取向样品的取向度为62.4%,磁导率实部值在2GHz时为4.8。
8.通过快淬方法制备纳米晶Sm2Fe14B微粉,研究了不同体积百分含量微粉／石蜡复合材料复数磁导率及复数介电常数随频率的变化。对于体积浓度为50%的样品,在最佳匹配频率点,样品的复数介电常数与复数磁导率的比值远大于1,与传统的在最佳匹配频率点复数介电常数等于复数磁导率的观点不同。复合材料在相对自由空间阻抗(Zin/Zo)为1时,出现了最佳匹配频率点(2.9GHz),反射吸收最小值达到了-42.0dB。
9.利用界面反射模型,解释了反射吸收峰出现的位置及强度。证明了界面反射对微波吸收性能的巨大影响,即使在完全吸收的条件下,电磁损耗所消耗的能量也只占了一小部分；
10.通过前界面涂覆,改变了样品反射回自由空间的能量,增强了样品微波吸收性能,近一步验证了界面反射模型的正确性。
Recently, electromagnetic (EM) wave devices have been widely used in both military and civil applications:radar, wireless communication tools, local area net works, personal digital assistant, etc. The frequency of EM wave has reached gigahertz (GHz) range. However, the increasing usage of EM waves in the GHz electromagnetic interference (EMI) and electromagnetic compatibility (EMC) problems which have drawn more attention as a specific kind of environmental pollution. To solve this problem, it is necessary to exploit a type of microwave absorption materials with thinner thickness, lighter weight, wider frequency band of microwave loss and more intensity of the microwave sbsorption. Complex permittivity and permeability of the absorbers play key roles in determining the absorption properties. According to the quarter-wavelength model, for metal magnetic absorbers, higher permeability and appropriate permittivity values are needed to satisfy the above demands. According to the bianisotropy theory, the easy-plane anisotropy materials can exceed the limit of the Snoek's limit and obtain a higher permeability in higher frequency range.
The shape planar anisotropy carbonyl-iron powder and magnetocrystalline easy-plane anisotropy rare-earth3d transition intermetallics have been prepared based on the bianisotropy theory. The dependence of the complex permeability, permittivity and the microwave absorption properties of these materials were investigated. On the other hand, we discussed the relation between the frequency of microwave loss, the thickness of the absorber and the complex permeability and permittivity. Moreover, the reflection of the reflective wave by the absorber and the perfect conductor to the microwave absorption properties was also investigated. According to the reflective loss model, we further improved the microwave absorption properties of the absorbers. The details and results of our research are listed as follows:
1. The choice of the easy-plane anisotropy materials. The morphology, static magnetic properties and high frequency properties of the ball milling particles will be different even in the same ball milling method, due to the different types of carbonyl-iron particles have different surface treatment. The RXEG and RXEL sphere-shaped carbonyl-iron particles were ball milling with400r/min for12hours. The ball milled RXEG particles have irregular shape, while the ball milled RXEL particles is flake-shaped. The thickness of the ball milled RXEL particles is lower than the skin depth of the iron particles, which induces that the permeability of the particles is almost constant up to2GHz. On the other hand, the permeability of the ball milling RXEG particles decreased rapidly with the increasing frequency.
2. To optimize the ball milling method. The RXEL sphere-shaped carbonyl-iron particles were ball milled under400r/min for8hs,12hs and16hs. The raw powders are deformed into thin flake particles after ball milling, and the flaky appears cold welding state for16hs ball milled particles. The permeability of the particles decreases and the resonance frequency shifts to lower frequency with increasing ball milling time. When ball milling time is used as8hs, the product of the permeability and the resonance frequency can maximum exceed the Snoek's limit. Then, the raw particles were ball milled under different speeds (200r/min,350r/min,400r/min,450r/min,500r/min,550r/min.) for8hs. The permeability of the samples are first increase and then decreased with increasing the ball milling speeds, which is consist with the change of the morphology and static magnetic properties. In summary, the raw particles are ball milled under500r/min for8hs possess a best frequency property.
3. In order to further optimize the high frequency properties and the microwave absorption properties of the easy-plane anisotropy canbonyl-iron particles. The easy-plane anisotropy canbonyl-iron/paraffin composite was oriented in an external magnetic field. The permeability of composite has an increasing factor of0.2-0.3than the nonoriented one. The resonance frequency and the permittivity of the oriented composite increase compared with the nonoriented one, and thus the matching thickness and the matching frequency decrease for the oriented composite.
4. To reduce the permittivity of the easy-plane anisotropy carbonyl-iron particles, the surface of the particles were coated with a thin layer of amorphous SiO2by Stober method. After coating SiO2layer, the permittivity of the easy-plane anisotropy carbonyl-iron/SiO2decreases significantly while the permeability shows a small decrease, which increase the threshold value of the volume fractions. By change the volume rate of the absolute ethyl alcohol/the water, the amount of the TEOS and the ammonia, the optimized condition of coating SiO2layer are obtained.
5. For the aim of thin electromagnetic wave absorbers used in quasimicrowave frequency band, easy-plane anisotropy carbonyl-iron (PACI) particles coated with ZnO nanoshells were prepared by ball milling technique and chemical precipitation method. Compared with the as-milled PACI/paraffin composite, lower electric constant was obtained for the composite containing PACI at ZnO particles, and hence a dramatic enhancement of reflection loss (RL) was obtained. The minimum RL of PACI at ZnO composite reaches-31.93dB at1.96GHz with the matching thickness of2.5mm. The PACI at ZnO core-shell particles exhibit great potential in application of the thin absorber in the1-4GHz frequency range.
6. easy-plane anisotropy carbonyl-iron (PACI)/Nio.5Zno.5Fe204composite as absorbent filler in quasimicrowave band has been synthesized via ball-milling technique and solvothermal method. The effective permeability of the composite was measured and calculated. The result indicates that the magnetic loss in the composite is mainly caused by the natural resonance. Compared with the uncoated PACI particles, the permittivity of the composite decreased dramatically, and hence a dramatic enhancement of reflection loss (RL) was obtained in quasimicrowave band. This result indicates that our PACI/ferrite composite can be used as potential microwave absorbers in quasimicrowave band for its novel microwave properties.
7. A new easy-plane anisotropy Ce2Fe17N3-δ compound as an electromagnetic absorption material was prepared by arc melting method. The influence of rotational orientation in various magnetic fields on the complex permeability and orientation degrees of the compound/paraffin composites were systematically studied. It is found that the orientation plays an important role in complex permeability and orientation degrees. For the composite with rotational orientation in1.6T, the real permeability reaches a large value of4.8at2GHz and the imaginary part reaches2.6at5.5GHz, on the other hand, the orientation degree reaches62.4%. It is evident that the oriented Ce2Fe17N3-δ composite with easy-plane anisotropy may have potential applications as microwave absorption materials.
8. A new easy-plane anisotropy Sm2Fe14B nanocrystal as an electromagnetic absorption material was prepared by melt spinning method. The electromagnetic and microwave absorbing properties of Sm2Fe14B nanocrystal/nonmagnetic matrix composite in the frequency range of0.1-10GHz were measured and calculated. At the perfect matching point (2.9GHz, vol.50%); the minimum reflection loss reaches-42.0dB at the matching thickness of3.1mm. Furthermore, the calculation shows that the normalized input impedance Zin/Zo equals to1, but the modulus of the ratio between the complex permittivity and permeability|ε/μ|is far away from unity at the perfect matching point.
9. The matching frequency and the intensity of reflection loss for the absorbers obey the quarter-wavelength model and the reflective loss model. The results show that the peak intensity of the RL is directly affected by the intensity of the reflective wave from the absorber layer and the emerging wave from the metal layer. The intensity of these two reflective waves dominates the intensity of the reflection loss even at the perfect matching point.
10. Coating a conductor layer in the front layer of the absorber can change the intensity of the reflective wave from the absorber layer interface and improve the microwave absorption properties of the absorbers.
引文
[1]韩瑞,兰州大学硕士论文,易面各向异性羰基铁颗粒高频磁性及微波吸收性能研究,2010。
[2]吴咏梅,张保国,军事史林6(2006)52-54.
[3]Wang, N. X. Sun, M. Yamaguchi and S. Yabukami,Nature 407,150 (2000)
[4]T. Tsutaoka, M. Ueshima, T. Tokunaga, T. Nakamura and K. Hatakeyama, J. Appl. Phys.78,3983 (1995).
[5]T. Nakamura, T. Tsutaoka and H. Hatakeyama, J. Mag. Mag. Mater.138,319 (1994)
[6]李萌远,铁氧体物理学,科学出版社,1978
[7]近角聪信,磁性体手册(下),北京冶金工业出版社,1948
[8]S. S. Kim, D. H. Han and S. B. Cho, IEEE. Trans. Magn.30,4554 (1994).
[9]S. B. Cho, D. H. Kang and J. H. Oh, J. Mater. Sci.31,4719 (1996)
[10]S. Chikazumi, Physics of Ferromagnetism.2nd ed., Oxford University Press, Oxford,1997.
[11]J. L. Snoek, Physica (Amsterdam) 14,207 (1948).
[12]G H. Jonker, H. P. J. Wijn and P. B. Brawn, Philips Tech.Rev.18,145 (1956).
[13]Z. W. Li, L. F. Chen and C. K. Ong, J. Appl. Phys.94,5918 (2003).
[14]Z. W. Li, L. F. Chen and C. K. Ong, J. Appl. Phys.92,3902(2002).
[15]Z. W. Li, G Q. Lin, L. F. Chen, Y. P. Wu and C. K. Ong, J. Appl. Phys.98,094310 (2005).
[16]Z. W. Li, Y. P. Wu, G Q. Lin and L. F. Chen, J. Mag. Mag. Mater.310,145 (2007)
[17]Z. W. Li, L. F. Chen, Y. P. Wu and C. K. Ong, J. Appl. Phys.96,534(2004).
[18]Y. P. Wu, C. K. Ong, Z. W. Li, L. F. Chen, G Q. Lin and S. J. Wang, J. Appl. Phys.97,063909 (2005).
[19]Y. P. Wu, Z. W. Li, L. F. Chen, S. J. Wang and C. K. Ong, J. Appl. Phys.95,4235 (2004).
[20]邓龙江,谢建良,梁启迪,等,功能材料,30,118(1990)
[21]都有为,铁氧体,南京：江苏科学技术出版社,1996
[22]张永祥,丁荣林,李韬,等,硅酸盐学报,26,275(1998)
[23]过璧君,邓龙江,电子科技大学学报,21,156(1992)
[24]G Viau, F. Ravel, O. Acher, F. Fievet-Vincent and F. Fievet, J. Mag. Mag. Mater.140-144,377 (1995)
[25]0. Acher and A. L. Adenot, Phys. Rev. B 62,11324 (2000)
[26]C. Brosseau and P. Talbot, J. Appl. Phys.97,104325 (2005).
[27]Y. B. Feng, T. Qiu, C. Y. Shen and X. Y. Li, IEEE. Trans. Magn.42,363 (2006).
[28]S. S. Kim, S. T. Kim, Y. C. Yoon and K. S. Lee, J. Appl. Phys.97,10F905 (2005).
[29]B. S. Zhang, Y. Feng, J. Xiong, Y. Yang and H. X. Lu, IEEE. Trans. Magn.42,1778 (2006).
[30]F. S. Wen, L. Qiang, H. B. Yi, D. Zhou and F. S. Li, Chin. Phys. Lett.25,751 (2008).
[31]F. S. Wen, L. Qiang, D. Zhou, W. L. Zuo, H. B. Yi and F. S. Li, Chin. Phys. B 17,2263 (2008)
[32]R. Skomski, J. Phys. Condens. Matter 15, R841 (2003).
[33]J. A. C. Bland and B. Heinrich (ed) Ultrathin Magnetic Structures vol 1 (Berlin:Springer)(1994).
[34]R. H. Victora and J. M. McLaren, Phys. Rev. B 47,11583 (1993). [35] G T. Rado and R. J. Hicken, J. Appl. Phys.,63,3885 (1988).
[36]J. G Gay and R. Richter, Phys. Rev. Lett.,56,2728 (1986).
[37]P. Bruno, Phys. Rev. B,39,865 (1989).
[38]G H. O. Daalderop, Kelly and M. F. H. Schuurmans, Phys. Rev. B 42,7270 (1990).
[39]D. S. Wang, R. Q. Wu and A. J. Freeman, Phys. Rev. B,47,14932 (1993).
[40]D. S. Wang, R. Q. Wu and A. J. Freeman, J. Appl. Phys.,75,6409 (1994).
[41]D. S. Wang, R. Q. Wu and A. J. Freeman, Phys. Rev. Lett.,70,869 (1993).
[42]G Viau, F. Fievet-Vincent, F. Fievet, P. Toneguzzo, F. Ravel and O. Acher, J. Appl. Phys.81,2749-2754 (1997).
[43]G Viau, F. Ravel, O. Acher, F. Fievet-Vincent and F. Fievet, J. Appl. Phys.76,6570-6572 (1994).
[44]K. Kondo, S. Yoshida, H. Ono and M. Abe, J. Appl. Phys.101,09M502-1-3 (2007).
[45]S. H. Ge, X. L. Yang, K. Y. Kim, L. Xi, X. M. Kou, D. S. Yao, B. S. Li and X. W. Wang, EEEE Trans, mag. 41,3307 (2005).
[46]O. Acher and A. L. Adenot, Phys. Rev. B 62,11324-11327 (2000).
[47]D. S. Xue, F. S. Li, X. L. Fan, F. S. Wen. Chin Phys Lett.11,4120-3 (2008).
[1]韩瑞,兰州大学硕士论文,易面各向异性羰基铁颗粒高频磁性及微波吸收性能研究,2010。
[2]廖绍彬,铁磁学(下册),科学出版社,1987。
[3]宛德福,马兴隆,磁性物理学,电子工业出版社,1999。
[4]J. L. Snoek. Physica (Amsterdam) 14,207 (1948).
[5]E. W. Gorter, Proc. IRE,43,245 (1955).
[6]Han R, Qiao L, Wang T, Li F-s. J Alloy Compd.2011;509:2734-7
[7]G H. Jonker, H. P. J. Wijn and P. B. Brawn, Philips Tech.Rev.18,145 (1956).
[8]电磁波屏蔽及吸波材料,刘顺华,刘军民,董星龙,化学工业出版社,2007.
[9]新型微波吸收材料,康青,科学出版社,2006.
[10]Z.W.Li,G. Q.Lin, and L.B.Kong,IEEE Trans.Magn.44,2255(2008).
[11]K. Ghosh and R. Fuchs. Phys. Rev. B.1988,38:5222-5236.
[12]L. Olmedo, G Chateau, C. Deleuze and J. L. Forveille. J. Appl. Phys.1993,73:6992-6994.
[13]K. N. Rozanov, A. V. Osipov, D. V. Petrov, S. N. Starostenko and E. P. Yelsukov. J. Magn. Magn. Mater.2009,321:738-741.
[1]机械合金化与固液反应球磨,陈振华,陈鼎,化学工业出版社,2006.
[2]C. Suryanarayana, Prog. Mater. Sci.46 (2001) 1-184.
[3]周庆韬,材料导报2(1992)17-21.
[4]X射线衍射分析原理与应用,刘粤惠,刘平安,化学工业出版社,2003.
[5]材料X射线衍射与电子显微分析,周玉,武高辉,哈尔滨工业大学出版社,1998.
[6]扫描电镜技术及其应用,郭素枝,厦门大学出版社,2006.
[7]磁性测量原理,周文生,电子工业出版社,1988.
[8]蒋晓红,空载雷达4(2002)69-79.
[9]兰州大学博士学位论文,乔亮,2009
[10]A. M. Nicolson, G F. Ross, IEEE Trans. Instrum. Meas.19 (1970) 377.
[11]马如璋,徐英庭主编.穆斯堡尔谱学.北京：科学出版社(1996).
[12]马如璋等编译.穆斯堡尔谱学手册.北京：冶金工业出版社(1993).
[13]电子显微分析,章晓中,清华大学出版社,2006.
[1]韩瑞,位建强,韩相华,伊海波,王涛,李发伸,科学通报55,2570-2575(2010).
[2]M Kopcewicz, T Lucinski, F Stobiecki, G Reiss, J. Appl. Phys.85 5039-5041 (1999).
[3]Han R, Qiao L, Wang T and Li F S. J. Alloys Compd.509:2734-2737 (2011).
[4]http://baike.baidu.com/view/4462841.htm.
[1]兰州大学硕士学位论文,闫陇刚,2008.
[2]Han, R. Han, X. H. Qiao, L. Wang, T. Li, F. S.. Advanced Materials Research,160-162,962-967 (2010).
[3]Han,R. Han, X.-h. Qiao,L. Wang, T. Li, F.-s., Physica B:Condensed Matter,406, (10),1932-1935 (2011).
[4]Han, R. Han, X.-h. Qiao, L. Wang, T. Li, F.-s., Materials Chemistry and Physics 128, (3),317322 (2011).
[5]Han, R. Gong, L.-q. Wang, T. Qiao, L. Li, F.-s., Materials Chemistry and Physics 131, (3),555-560 (2012).
[1]Han, R. Yi, H.-b. Zuo, W.-l. Wang, T. Qiao, L. Li, F.-s., Journal of Magnetism and Magnetic Materials 324, (16),2488-2491 (2012).
[2]Han, R. Yi, H.-b. Wei J-q, Wang, T. Qiao, L. Li, F.-s., Applied physics A (doi: 10.1007/s00339-012-6948-9).
[2]吴咏梅,张保国,军事史林6(2006)52-54.
[3]Wang, N. X. Sun, M. Yamaguchi and S. Yabukami,Nature 407,150 (2000)
[4]T. Tsutaoka, M. Ueshima, T. Tokunaga, T. Nakamura and K. Hatakeyama, J. Appl. Phys.78,3983 (1995).
[5]T. Nakamura, T. Tsutaoka and H. Hatakeyama, J. Mag. Mag. Mater.138,319 (1994)
[6]李萌远,铁氧体物理学,科学出版社,1978
[7]近角聪信,磁性体手册(下),北京冶金工业出版社,1948
[8]S. S. Kim, D. H. Han and S. B. Cho, IEEE. Trans. Magn.30,4554 (1994).
[9]S. B. Cho, D. H. Kang and J. H. Oh, J. Mater. Sci.31,4719 (1996)
[10]S. Chikazumi, Physics of Ferromagnetism.2nd ed., Oxford University Press, Oxford,1997.
[11]J. L. Snoek, Physica (Amsterdam) 14,207 (1948).
[12]G H. Jonker, H. P. J. Wijn and P. B. Brawn, Philips Tech.Rev.18,145 (1956).
[13]Z. W. Li, L. F. Chen and C. K. Ong, J. Appl. Phys.94,5918 (2003).
[14]Z. W. Li, L. F. Chen and C. K. Ong, J. Appl. Phys.92,3902(2002).
[15]Z. W. Li, G Q. Lin, L. F. Chen, Y. P. Wu and C. K. Ong, J. Appl. Phys.98,094310 (2005).
[16]Z. W. Li, Y. P. Wu, G Q. Lin and L. F. Chen, J. Mag. Mag. Mater.310,145 (2007)
[17]Z. W. Li, L. F. Chen, Y. P. Wu and C. K. Ong, J. Appl. Phys.96,534(2004).
[18]Y. P. Wu, C. K. Ong, Z. W. Li, L. F. Chen, G Q. Lin and S. J. Wang, J. Appl. Phys.97,063909 (2005).
[19]Y. P. Wu, Z. W. Li, L. F. Chen, S. J. Wang and C. K. Ong, J. Appl. Phys.95,4235 (2004).
[20]邓龙江,谢建良,梁启迪,等,功能材料,30,118(1990)
[21]都有为,铁氧体,南京：江苏科学技术出版社,1996
[22]张永祥,丁荣林,李韬,等,硅酸盐学报,26,275(1998)
[23]过璧君,邓龙江,电子科技大学学报,21,156(1992)
[24]G Viau, F. Ravel, O. Acher, F. Fievet-Vincent and F. Fievet, J. Mag. Mag. Mater.140-144,377 (1995)
[25]0. Acher and A. L. Adenot, Phys. Rev. B 62,11324 (2000)
[26]C. Brosseau and P. Talbot, J. Appl. Phys.97,104325 (2005).
[27]Y. B. Feng, T. Qiu, C. Y. Shen and X. Y. Li, IEEE. Trans. Magn.42,363 (2006).
[28]S. S. Kim, S. T. Kim, Y. C. Yoon and K. S. Lee, J. Appl. Phys.97,10F905 (2005).
[29]B. S. Zhang, Y. Feng, J. Xiong, Y. Yang and H. X. Lu, IEEE. Trans. Magn.42,1778 (2006).
[30]F. S. Wen, L. Qiang, H. B. Yi, D. Zhou and F. S. Li, Chin. Phys. Lett.25,751 (2008).
[31]F. S. Wen, L. Qiang, D. Zhou, W. L. Zuo, H. B. Yi and F. S. Li, Chin. Phys. B 17,2263 (2008)
[32]R. Skomski, J. Phys. Condens. Matter 15, R841 (2003).
[33]J. A. C. Bland and B. Heinrich (ed) Ultrathin Magnetic Structures vol 1 (Berlin:Springer)(1994).
[34]R. H. Victora and J. M. McLaren, Phys. Rev. B 47,11583 (1993). [35] G T. Rado and R. J. Hicken, J. Appl. Phys.,63,3885 (1988).
[36]J. G Gay and R. Richter, Phys. Rev. Lett.,56,2728 (1986).
[37]P. Bruno, Phys. Rev. B,39,865 (1989).
[38]G H. O. Daalderop, Kelly and M. F. H. Schuurmans, Phys. Rev. B 42,7270 (1990).
[39]D. S. Wang, R. Q. Wu and A. J. Freeman, Phys. Rev. B,47,14932 (1993).
[40]D. S. Wang, R. Q. Wu and A. J. Freeman, J. Appl. Phys.,75,6409 (1994).
[41]D. S. Wang, R. Q. Wu and A. J. Freeman, Phys. Rev. Lett.,70,869 (1993).
[42]G Viau, F. Fievet-Vincent, F. Fievet, P. Toneguzzo, F. Ravel and O. Acher, J. Appl. Phys.81,2749-2754 (1997).
[43]G Viau, F. Ravel, O. Acher, F. Fievet-Vincent and F. Fievet, J. Appl. Phys.76,6570-6572 (1994).
[44]K. Kondo, S. Yoshida, H. Ono and M. Abe, J. Appl. Phys.101,09M502-1-3 (2007).
[45]S. H. Ge, X. L. Yang, K. Y. Kim, L. Xi, X. M. Kou, D. S. Yao, B. S. Li and X. W. Wang, EEEE Trans, mag. 41,3307 (2005).
[46]O. Acher and A. L. Adenot, Phys. Rev. B 62,11324-11327 (2000).
[47]D. S. Xue, F. S. Li, X. L. Fan, F. S. Wen. Chin Phys Lett.11,4120-3 (2008).
[1]韩瑞,兰州大学硕士论文,易面各向异性羰基铁颗粒高频磁性及微波吸收性能研究,2010。
[2]廖绍彬,铁磁学(下册),科学出版社,1987。
[3]宛德福,马兴隆,磁性物理学,电子工业出版社,1999。
[4]J. L. Snoek. Physica (Amsterdam) 14,207 (1948).
[5]E. W. Gorter, Proc. IRE,43,245 (1955).
[6]Han R, Qiao L, Wang T, Li F-s. J Alloy Compd.2011;509:2734-7
[7]G H. Jonker, H. P. J. Wijn and P. B. Brawn, Philips Tech.Rev.18,145 (1956).
[8]电磁波屏蔽及吸波材料,刘顺华,刘军民,董星龙,化学工业出版社,2007.
[9]新型微波吸收材料,康青,科学出版社,2006.
[10]Z.W.Li,G. Q.Lin, and L.B.Kong,IEEE Trans.Magn.44,2255(2008).
[11]K. Ghosh and R. Fuchs. Phys. Rev. B.1988,38:5222-5236.
[12]L. Olmedo, G Chateau, C. Deleuze and J. L. Forveille. J. Appl. Phys.1993,73:6992-6994.
[13]K. N. Rozanov, A. V. Osipov, D. V. Petrov, S. N. Starostenko and E. P. Yelsukov. J. Magn. Magn. Mater.2009,321:738-741.
[1]机械合金化与固液反应球磨,陈振华,陈鼎,化学工业出版社,2006.
[2]C. Suryanarayana, Prog. Mater. Sci.46 (2001) 1-184.
[3]周庆韬,材料导报2(1992)17-21.
[4]X射线衍射分析原理与应用,刘粤惠,刘平安,化学工业出版社,2003.
[5]材料X射线衍射与电子显微分析,周玉,武高辉,哈尔滨工业大学出版社,1998.
[6]扫描电镜技术及其应用,郭素枝,厦门大学出版社,2006.
[7]磁性测量原理,周文生,电子工业出版社,1988.
[8]蒋晓红,空载雷达4(2002)69-79.
[9]兰州大学博士学位论文,乔亮,2009
[10]A. M. Nicolson, G F. Ross, IEEE Trans. Instrum. Meas.19 (1970) 377.
[11]马如璋,徐英庭主编.穆斯堡尔谱学.北京：科学出版社(1996).
[12]马如璋等编译.穆斯堡尔谱学手册.北京：冶金工业出版社(1993).
[13]电子显微分析,章晓中,清华大学出版社,2006.
[1]韩瑞,位建强,韩相华,伊海波,王涛,李发伸,科学通报55,2570-2575(2010).
[2]M Kopcewicz, T Lucinski, F Stobiecki, G Reiss, J. Appl. Phys.85 5039-5041 (1999).
[3]Han R, Qiao L, Wang T and Li F S. J. Alloys Compd.509:2734-2737 (2011).
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