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21.
P. T. Jochym K. Parlinski A. M. Oleś 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,61(2):173-179
The magnetization distribution, its energetic characterization by the
interlayer coupling constants and lattice dynamics of (001)-oriented
Fe/Pt multilayers are investigated using density functional theory
combined with the direct method to determine phonon frequencies.
It is found that ferromagnetic order between consecutive Fe layers is
favoured, with the enhanced magnetic moments at the
interface. The bilinear and biquadratic coupling coefficients between Fe
layers are shown to saturate fast with increasing thickness of
nonmagnetic Pt layers which separate them. The phonon calculations
demonstrate a rather strong dependence of partial iron phonon
densities of states on the actual position of Fe monolayer
in the multilayer structure. 相似文献
22.
23.
A. I. Belousova Yu. E. Lozovikb 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,8(2):251-264
A two dimensional (2D) classical system of dipole particles confined by a quadratic potential is studied. This system can
be used as a model for rare electrons in semiconductor structures near a metal electrode, indirect excitons in coupled quantum
dots etc. For clusters of N ≤ 80 particles ground state configurations and appropriate eigenfrequencies and eigenvectors for the normal modes are found.
Monte-Carlo and molecular dynamic methods are used to study the order-disorder transition (the “melting” of clusters). In
mesoscopic clusters (N < 37) there is a hierarchy of transitions: at lower temperatures an intershell orientational disordering of pairs of shells
takes place; at higher temperatures the intershell diffusion sets in and the shell structure disappears. In “macroscopic”
clusters (N > 37) an orientational “melting” of only the outer shell is possible. The most stable clusters (having both maximal lowest
nonzero eigenfrequencies and maximal temperatures of total melting) are those of completed crystal shells which are concentric
groups of nodes of 2D hexagonal lattice with a number of nodes placed in the center of them. The picture of disordering in
clusters is compared with that in an infinite 2D dipole system. The study of the radial diffusion constant, the structure
factor, the local minima distribution and other quantities shows that the melting temperature is a nonmonotonic function of
the number of particles in the system. The dynamical equilibrium between “solid-like” and “orientationally disordered” forms
of clusters is considered. 相似文献
24.
利用射频磁控溅射系统在不同N2分压的条件下,制备了一系列ZrN/WN纳米多层膜.借助慢正电子湮没技术分析了样品的缺陷性质,采用纳米压痕仪研究了多层膜的力学性能.结果发现:N2分压为0.4Pa的多层膜具有最小的空位型缺陷浓度,其中心层和膜基结合层的平均S参数分别为0.4402和0.4641,而较低或较高的N2分压都可能导致空位型缺陷浓度的增加.随着空位型缺陷浓度的减小,多层膜的硬度和临界载荷增大.对于空位型缺陷浓度最小的多层膜,其硬度和临界载荷达到最大值,分别为34.8GPa和100mN,说明较低的缺陷浓度有利于提高多层膜的力学性能.
关键词:
ZrN/WN纳米多层膜
缺陷性质
力学性能
慢正电子湮没 相似文献
25.
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
26.
Magnetic anisotropy manipulation and interfacial coupling in Sm3Fe5O12 films and CoFe/Sm3Fe5O12 heterostructures
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The magnetic anisotropy manipulation in the Sm3Fe5O12 (SmIG) films and its effect on the interfacial spin coupling in the CoFe/SmIG heterostructures were studied carefully. By switching the orientation of the Gd3Ga5O12 substrates from (111) to (001), the magnetic anisotropy of obtained SmIG films shifts from in-plane to out-of-plane. Similar results can also be obtained in the films on Gd3Sc2Ga3O12 substrates, which identifies the universality of such orientation-induced magnetic anisotropy switching. Additionally, the interfacial spin coupling and magnetic anisotropy switching effect on the spin wave in CoFe/SmIG magnetic heterojunctions have also been explored by utilizing the time-resolved magneto-optical Kerr effect technique. It is intriguing to find that both the frequency and effective damping factor of spin precession in CoFe/SmIG heterojunctions can be manipulated by the magnetic anisotropy switching of SmIG films. These findings not only provide a route for the perpendicular magnetic anisotropy acquisition but also give a further path for spin manipulation in magnetic films and heterojunctions. 相似文献
27.
垂直磁各向异性稀土-铁-石榴石纳米薄膜在自旋电子学中具有重要应用前景.本文使用溅射方法在(111)取向掺杂钇钪的钆镓石榴石(Gd0.63Y2.37Sc2Ga3O12,GYSGG)单晶衬底上外延生长了2—100 nm厚的钬铁石榴石(Ho3Fe5O12,HoIG)薄膜,并进一步在HoIG上沉积了3 nm Pt薄膜.测量了室温下HoIG的磁各向异性和HoIG/Pt异质结构的自旋相关输运性质.结果显示,厚度薄至2 nm的HoIG薄膜(小于2个单胞层)在室温仍具有铁磁性,且由于外延应变,2—60 nm厚HoIG薄膜都具有很强的垂直磁各向异性,有效垂直各向异性场最大达350 mT;异质结构样品表现出非常可观的反常霍尔效应和“自旋霍尔/各向异性”磁电阻效应,前者在HoIG厚度小于4 nm时开始缓慢下降,而后者当HoIG厚度小于7 nm时急剧减小,说明相较于反常霍尔效应,磁电阻效应对HoIG的体磁性相对更加敏感;此外,自旋相关热电压随HoIG厚度减薄在整个厚度范围以指数方式下降,说明遵从热激化磁振子运动规律的自旋塞贝克效应是其主要贡献者.本文结果表明HoIG纳米薄膜具有可调控的垂直磁各向异性,厚度大于4 nm的HoIG/Pt异质结构具有高效的自旋界面交换作用,是自旋电子学应用发展的一个重要候选材料. 相似文献
28.
X‐ray standing wave (XSW) field generated under Bragg reflection condition in a periodic Mo/Si multilayer structure has been used to determine the concentration and location of various trace element contaminants embedded in different layers of that multilayer structure. We have used intense synchrotron X rays for XSW analysis. It is observed that various trace element impurities such as Cr, Fe, Ni and W get embedded unintentionally in the multilayer structure during the deposition process. Consequences of such impurity incorporation on the optical properties of the multilayer structure are discussed in hard and soft X‐ray regions. Present measurements are important in order to optimize the deposition methods on one hand and to better correlate the measured optical properties of a multilayer structure with theoretical models on the other. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
29.
Zhanwei Xu Huijuan Luo Huihui Sun Qinglin Zhang Gaoxiang Cao Kezhi Li 《Solid State Communications》2011,151(8):643-646
Graphite nanosheets (GNs) doped with N, Fe, or Ni were synthesized by pyrolysis of metal tetrapyridinoporphyrazine (MPTpz, M=Fe2+, and Ni2+) and a mixture of MPTpzs in a chemical vapor deposition furnace. The products obtained were characterized by scanning and transmission electron microscopy, and X-ray photoelectron spectroscopy. The magnetic properties of the GNs obtained were investigated at room temperature using a vibrating sample magnetometer with an applied field of −10 000-10 000 Gs. The results show the GNs obtained are terrace-like and ultra-thin, with very high aspect ratio. Fe, Ni and N atoms have been doped to the GNs successfully. There are two types of N atom that are introduced into pure carbon systems: pyrinidic and graphitic N atoms. The GNs obtained exhibit ferromagnetic behavior at room temperature. Sample S1, obtained by pyrolysis of a mixture of MPTpzs (M=Fe2+ and Ni2+), have the highest coercivity force. The saturation magnetization (Ms), remanent magnetization (Mr), and coercivity (Hc) values of sample S1 are 24.51 emu g−1, 3.95 emu g−1, and 207.34 Gs, respectively. 相似文献
30.
The comment by Lin He proposes that at the interface between holmium and cobalt an interesting magnetic proximity effect occurs in which the spiral magnetic wavelength (λ) of holmium is enhanced to 5.4 nm. Consequently, the optimum holmium layer thickness for the superconductor spin triplet proximity effect to occur in Nb/Ho/Co/Ho/Nb Josephson junctions of ≈4.5 and ≈10 nm would then correspond to the presence of ≈λ/2 and ≈3λ/2 spiral wavelengths. Although intriguing, this idea seems to be at odds with the conventional micromagnetics of either thin film (polycrystalline) holmium or single-crystal Ho at low temperatures (10 K). Although an increase in λ in Ho/metal multilayer thin films with epitaxially matched interfaces has been reported, the possibility of such an effect in a polycrystalline system seems unlikely. 相似文献