共查询到19条相似文献,搜索用时 651 毫秒
1.
利用磁控溅射法制备了Nd28Fe66B6/Fe50Co50 双层纳米复合磁性薄膜,研究了其结构和磁性.经873K退火处理15min 后,利用x射线衍射仪测定薄膜晶体结构,采用俄歇电子能谱仪估算薄膜厚度和超导量子干 涉仪测量其磁性.磁性测量表明,1)该系列薄膜具有垂直于膜面的磁各向异性.从起始磁化曲 线和小回线的形状特征可知,矫顽力机制主要是由畴壁钉扎控制.2)对于固定厚度(10nm) 层的硬磁相Nd-Fe-B和不同厚度(dFeCo=1—100nm)层软磁相FeCo双层纳米复合 膜,剩磁随软磁相FeCo 厚度的增加快速增加,而矫顽力则减少.当dFeCo=5nm 时 ,最大磁能积达到160×103A/m.磁滞回线的单一硬磁相特征说明,硬磁相Nd -Fe-B层和软磁相FeCo层之间的相互作用使两相很好地耦合在一起.剩磁和磁能积的提高是由 于两相磁性交换耦合所致.
关键词:
Nd-Fe-B/FeCo双层纳米复合膜
交换耦合
磁性增强 相似文献
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制备了Nd28Fe66B6/Fe50Co50多层纳米复合磁性薄膜,对溅射态和650℃退火处理15 min试样的相成分分析和微结构的观察显示,溅射态薄膜呈非晶态,经650℃退火处理15 min后,薄膜主要相成分为硬磁性Nd2Fe14B相和软磁性相FeCo(110)相.Nd2Fe14B相呈柱状,其易磁化c轴垂直于膜面,尺寸约10 nm.在硬磁性相和软磁性相之间存在少量富Nd相和非晶态,富Nd相大小约7 nm.磁性测量和分析表明,1)该系列薄膜退火态具有垂直于膜面的磁晶各向异性.2)对于固定厚度(10 nm)层Nd-Fe-B和不同厚度(tFeCo=1—100 nm)层FeCo多层纳米复合膜,剩磁随软磁相FeCo 厚度的增加快速增加,而矫顽力则减小.当tFeCo=5 nm时,最大磁能积达到200 kJ/m3. 3)硬磁相Nd-Fe-B层和软磁相FeCo层之间交换耦合导致剩磁和磁能积增强.
关键词:
Nd-Fe-B/FeCo多层纳米复合膜
交换耦合
磁各向异性 相似文献
4.
用正电子湮没技术、1000kV超高压电子显微镜结合磁测量研究了SmCo5永磁合金在回火中相析出和矫顽力机制。得出:从SmCo5析出的Sm2Co17相本身不是反磁化形核中心,析出的Sm2Co17相中存在的某些多缺陷区域可以具有很低的磁各向异性,从而成为反磁化形核中心,使内禀矫顽力下降。实验中发现:SmCo5从25℃到900℃回火,750℃出现最大磁不可逆损失。各种近邻Sm3+分布的中心Sm3+的磁各向异性随温度变化,越接近Sm2Co17结构,Sm3+为负磁各向异性的可能性越大。
关键词: 相似文献
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利用表面磁光克尔效应和铁磁共振对分子束外延生长的Fe/Fe50Mn50双层膜的交换偏置场和矫顽力进行了研究,实验结果表明,当反铁磁层厚度小于55nm时 ,不出现交换偏置,而当大于这一厚度时,出现交换偏置;大约在7nm时,达到极大值.随着 反铁磁层厚度的继续增大,偏置场和矫顽力随Fe50Mn50膜厚的增大 而下降.铁磁共振实验结果表明样品的磁性存在单向各向异性.并对上述结果进行了讨论.
关键词:
分子束外延
50Mn50')" href="#">Fe/Fe50Mn50
双层膜
交换偏置 相似文献
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运用三维数值模拟计算方法,计算了膜面外不同易轴取向下Nd2Fe14B/Fe65Co35磁性双层膜的磁滞回线、角度分布、成核场、矫顽力和磁能积等,并与实验结果进行了细致比较.计算结果表明:只有当易轴与外场之间的夹角β=0?时,才有明显的成核现象,其成核场和矫顽力均随着软磁相厚度Ls的增加而降低;随着易轴偏角β的增大,剩磁逐渐减小,磁滞回线的方形度降低,从而磁能积减小,在Ls=1 nm,β=0?时磁能积(561.61 kJ/m3)最大.理论计算所得的磁滞回线与实验磁滞回线符合得很好,剩磁和矫顽力的理论值与实验值相差很小. 相似文献
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运用微磁学方法结合物质参数探究了垂直取向Nd2Fe14B/α-Fe磁性三层膜的磁化反转过程,计算出成核场、钉扎场以及磁滞回线随Ls(软磁相厚度)的变化,并与相关的实验和理论数据进行比较.由于考虑了退磁能量项,垂直取向的成核场比平行取向时低,在外磁场还没有反向时就发生了成核.随着软磁相厚度的增加,理论矫顽力从等于成核场(同时也等于钉扎场),到等于钉扎场,再到小于钉扎场,矫顽力机理由成核变为钉扎.
关键词:
成核场
钉扎场
矫顽力
磁滞回线 相似文献
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用电弧熔炼法制备了Nd3.6Pr5.4Fe83Co3B5合金铸锭,然后利用熔旋快淬法在铜辊转速V=20m/s下制备了Nd3.6Pr5.4Fe83Co3B5薄带.快淬带主要由软磁相α-Fe和Nd2Fe14B型的硬磁相组成.采用直流退磁剩磁曲线方法分析了样品在反磁化过程中的可逆与不可逆磁化部分,并研究了软磁相和硬磁相的反磁化行为,得到样品的不可逆磁化形核场Hno约为440kA/m.同时研究了样品的磁黏滞性,结果表明由于软磁相的存在使得热激活体积较大.
关键词: 相似文献
11.
Jihong Chen Yuwei Li Baoshan Zhang Yi Yang Mu Lu Huaixian Lu 《Journal of magnetism and magnetic materials》2010,322(20):3109-3111
[NiO/Fe65Co35]10 exchange-coupled multilayer films for high frequency applications are fabricated, and their static magnetic property and microwave permeability are studied systematically. Both exchange bias field and ferromagnetic resonance frequency of the multilayers increase with decreasing Fe65Co35 thickness, which means that the microwave properties such as permeability and FMR frequency can be controlled by changing Fe65Co35 thickness in the exchange-coupled films. Ferromagnetic resonance frequencies beyond 7 GHz of the films are measured and reported for the first time. 相似文献
12.
Rujun Tang Sherlyn ChuaWanli Zhang Yanrong Li 《Journal of magnetism and magnetic materials》2011,323(21):2569-2574
The anisotropy of the soft layer in the Co100−xPtx/Co71Pt29 (x=0, 7 and 17) perpendicular exchange-coupled composite (ECC) films was varied by changing the Pt content. The effects of soft layer softness (thickness and anisotropy) on the coercivity and magnetization reversal mechanisms of ECC were studied. Results showed that both remanence ratio (Mr/Ms) and coercivity of the ECC films reduced with an increase in soft layer thickness. However, the rate of coercivity reduction reduced when soft layer anisotropy was increased simultaneously. This was confirmed by the following facts. For the ECC with Co soft layer, the magnetization reversal mechanism within the ECC grains changed from coherent rotation to domain wall motion when soft layer thickness was changed from 2 to 15 nm. The impact of soft layer thickness on the magnetization reversals of the ECC grains reduced with an increase in soft layer anisotropy. On the other hand, the change of soft layer easy axis direction could possibly change the reversal mechanism of the ECC grains. The above experimental results showed that the coercivity of ECC film was controlled by the reversal mechanism inside the ECC grains. 相似文献
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《Journal of magnetism and magnetic materials》2002,251(2):202-206
We present results of magnetization and magnetic anisotropy measurements in thin magnetic films of the alloys Ni81Fe19, Co90Fe10 and Ni65Fe15Co20 that are commonly used in magnetoelectronic devices. The films were sandwiched between layers of Ta. At room temperature the critical thickness for all the films to become ferromagnetic is in the range 11–13 Å. In Co90Fe10 the coercivity and the anisotropy field both depend strongly on layer thickness. 相似文献
14.
《Journal of magnetism and magnetic materials》2002,249(3):458-461
Magnetic and structural properties of the arrays of 18 nm diameter nanowires of Co and Co90Fe10 electrodeposited in the pores of anodic alumina are investigated. Arrays of Co and Co90Fe10 nanowires show perpendicular magnetic anisotropy and textured crystallographic behaviour. Coercivity Hc (⊥) and remanence Mr/Ms (⊥) values of 2275 Oe (Co90Fe10); 1188 Oe (Co) and 96% (Co90Fe10), 81% (Co) are observed. The continuous films of Co and Co90Fe10 on Cu substrates show in plane magnetic anisotropy and coercivity values between 109 and 288 Oe. 相似文献
15.
Wang L. S. Liu S. J. Guo H. Z. Chen Y. Yue G. H. Peng D. L. Hihara T. Sumiyama K. 《Applied Physics A: Materials Science & Processing》2012,106(3):717-723
The ferromagnetic transparent conducting film is a multifunctional film which has high visible transmittance, low resistivity
and room-temperature ferromagnetism, simultaneously. In this article, ferromagnetic transparent conducting ZnO:Al/Fe65Co35/ZnO:Al multilayer films were fabricated by inserting a middle magnetic Fe65Co35 layer into aluminum-doped zinc oxide (ZnO:Al) matrix using a magnetron sputtering apparatus at substrate temperature ranging
from room temperature (RT) to 400∘C. The total film thickness was about 400 nm and the middle Fe65Co35 alloy layer was 4 nm. The influences of substrate temperature (T
s
) on the structural, electrical, optical and magnetic properties of the multilayer films were systemically investigated. The
results showed that the microstructure and performance of the composite multilayer films strongly depended on the substrate
temperature. The present results also showed that the inserted middle Fe65Co35 alloy thin layer played an important role in providing the RT ferromagnetism and decreasing the resistivity of the multilayer films. Therefore, it is possible to obtain a multifunctional
film material with the combination of good optical transparency, high electrical conductivity and RT ferromagnetism. 相似文献
16.
Crystal structure and magnetic properties of hard magnetic Sm2Fe17Nδ thin films with Co substitution
The crystal structure and magnetic properties of the hard magnetic Sm2(Fe1−xCox)17Nδ thin films prepared by dc magnetron sputtering and subsequent nitrogenation process were investigated. It is found that the N content and crystal structure determine the non-monotonic dependence of the coercivity HC on nitriding temperature for the films with x=0. With nitriding temperature exceeding 300 °C, N atoms can enter the Sm2Fe17 phase and the N content increases with increasing nitriding temperature, which leads to an increased coercivity. However, the maximum value of the HC is observed at 400 °C. The α-Fe soft phase appears with nitriding temperature further increasing to 500 °C, which is responsible for the decreased HC. When x is between 0 and 0.36, the films exhibit single Th2Zn17-type structure. Co atoms are found to go into the lattice of the 2:17 phase, generating an enhanced exchange coupling interaction between the nano-grains, which is responsible for the improved hard magnetic properties of the films with Co substitution at a certain range. Especially, the optimal value of the coercivity HC and remanence ratio MR/MS reaches 4.0 kOe and 0.70 for the films with x=0.17 and 0.36, respectively. 相似文献
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《Chinese Journal of Physics (Taipei)》2018,56(4):1789-1798
M-type hexaferrites with Co2+ and Ni2+ions substituting for Fe3+ ions (Ca0.30Sr0.35La0.35Fe12.0−x(Co0.5Ni0.5)xO19, 0.0 ≤ x ≤ 1.0) were prepared by the traditional solid state method. X-ray diffractometer (XRD), field emission scanning electron microscopy (FE-SEM), physical property measurement system-vibrating sample magnetometer (PPMS-VSM) have been employed to study the microstructures and magnetic properties of hexaferrites. XRD patterns showed that the single magnetoplumbite phase is obtained if Co–Ni content (x) ≤ 0.4 and impurity phases are observed in the structure when Co–Ni content (x) ≥ 0.4. FE-SEM micrographs showed that the hexaferrites with hexagonal platelet-like grains is obtained. The saturation magnetization (Ms), remanent magnetization (Mr), Mr/Ms ratio, magneton number (nB), coercivity (Hc), magnetic anisotropy field (Ha) and first anisotropy constant (K1) decrease with increasing Co–Ni content (x) from 0.0 to 1.0. And our reported results with tunable Hc and Mr can be used for recording applications. 相似文献
19.
The structure, magnetic properties and magnetostriction of Fe81Ga19 thin films have been investigated by using X-ray diffraction analysis, scanning electron microscope (SEM), vibrating sample magnetometer and capacitive cantilever method. It was found that the grain size of as-deposited Fe81Ga19 thin films is 50–60 nm and the grain size increases with increase in the annealing temperature. The remanence ratio (Mr/Ms) of the thin films slowly decreases with increase in the annealing temperature. However, the coercivity of the thin films goes the opposite way with increase in the annealing temperature. A preferential orientation of the Fe81Ga19 thin film fabricated under an applied magnetic field exists along 〈1 0 0〉 direction due to the function of magnetic field during sputtering. An in-plane-induced anisotropy of the thin film is well formed by the applied magnetic field during the sputtering and the formation of in-plane-induced anisotropy results in 90° rotations of the magnetic domains during magnetization and in the increase of magnetostriction for the thin film. 相似文献