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1.
Cerium dioxide thin film optical waveguides were fabricated by an RF magnetron sputtering process. The films were deposited on glass substrates and on silicon dioxide layers grown on silicon substrates. Optical loss measurements for the fabricated waveguides are reported. It is seen that the volume losses in the films were fairly high compared with the surface losses. 相似文献
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M.J.M. Pires A.A.C. CottaM.D. Martins A.M.A. SilvaW.A.A. Macedo 《Journal of magnetism and magnetic materials》2011,323(6):789-793
The development of devices based on magnetic tunnel junctions has raised new interests on the structural and magnetic properties of the interface Co/MgO. In this context, we have grown ultrathin Co films (≤30 Å) by molecular-beam epitaxy on MgO(0 0 1) substrates kept at different temperatures (TS). Their structural and magnetic properties were correlated and discussed in the context of distinct magnetic anisotropies for Co phases reported in the literature. The sample characterization has been done by reflection high energy electron diffraction, magneto-optical Kerr effect and ferromagnetic resonance. The main focus of the work is on a sample deposited at TS=25 °C, as its particular way of growth has enabled a bct Co structure to settle on the substrate, where it is not normally obtained without specific seed layers. This sample presented the best crystallinity, softer magnetic properties and a four-fold in-plane magnetic anisotropy with Co〈1 1 0〉 easy directions. Concerning the samples prepared at TS=200 and 500° C, they show fcc and polycrystalline structures, respectively and more intricate magnetic anisotropy patterns. 相似文献
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Leszek Malkinski Nicholas Cramer Andrew Hutchison Robert Camley Zbigniew Celinski Danuta Skrzypek Ron B. Goldfarb 《Journal of magnetism and magnetic materials》2002,240(1-3):261-263
A new type of ferromagnet/antiferromagnet structure (Fe/KCoF3) was deposited by molecular beam epitaxy. Unidirectional and uniaxial anisotropies of 5.1 and 3.4 kA/m were measured at 23 K using ferromagnetic resonance. Magnetization measurements at 5 K showed a hysteresis loop shift of 6 kA/m due to exchange bias. Significant enhancement of four-fold anisotropy was found at low temperatures in the samples with polycrystalline KCoF3 structure. 相似文献
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Theoretical investigation of ferromagnetic resonance in a ferromagnetic thin film with external stress anisotropy 下载免费PDF全文
We use the ferromagnetic resonance(FMR)method to study the properties of ferromagnetic thin film,in which external stress anisotropy,fourfold anisotropy and uniaxial anisotropy are considered.The analytical expressions of FMR frequency,linewidth and the imaginary part of magnetic susceptibility are obtained.Our results reveal that the FMR frequency and the imaginary part of magnetic susceptibility are distinctly enhanced,and the frequency linewidth or field linewidth are broadened due to a strong external stress anisotropy field.The hard-axis and easy-axis components of magnetization can be tuned significantly by controlling the intensity and direction of stress and the in-plane uniaxial anisotropy field. 相似文献
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采用铁磁共振方法,研究了铁磁/反铁磁双层薄膜中交换各向异性和应力各向异性对其物理性质的影响.结果表明,单向各向异性来源于界面交换作用,应力各向异性对材料的磁化难易程度有较大影响.当外磁场方向与应力场方向平行时,应力场的存在将促进该方向的磁化.反之,应力场将会阻碍该方向的磁化. 相似文献
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U. Bauer M. DabrowskiM. Przybylski J. Kirschner 《Journal of magnetism and magnetic materials》2011,323(11):1501-1508
So-called split hysteresis loops have been measured for ultrathin ferromagnetic films grown on stepped surfaces. Since the shape of the loops is sensitive to the direction in which the magnetic field is applied with respect to the steps, the sample orientation against the field is particularly important. We performed systematic magneto-optical Kerr effect studies for 15 and 58 ML of Fe grown on Au(1,1,13). In view of the complex magnetic anisotropy of such systems we discuss representative hysteresis loops taken at sample orientations misaligned from the field (and laser beam) direction. In particular, the presence of a so-called low field component to the hysteresis loops is discussed and its reversed polarity is explained. 相似文献
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Annealing effect on ion-beam-sputtered titanium dioxide film 总被引:3,自引:0,他引:3
We found that the extinction coefficient of ion-beam-sputtered titanium dioxide films first decreased with increasing annealing temperature then increased drastically when annealing temperature was increased above ~200 degrees C for 24 h of annealing time. The decreasing extinction coefficient with annealing temperature was attributed to a reduction in absorption owing to oxidation of the film by annealing. The film structure remained amorphous to 200 degrees C annealing temperature. The drastic increase of extinction coefficients above ~200 degrees C was associated with the appearance of an anatase polycrystalline structure and was attributed to scattering by the polycrystalline structure. With shorter annealing time the transition temperature from amorphous to polycrystalline anatase was higher. Guidance for reducing the optical loss of laser mirrors is proposed. 相似文献
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具有条纹磁畴结构的磁性薄膜表现出面内转动磁各向异性,对于解决高频电子器件的方向性问题起着至关重要的作用.本文采用射频磁控溅射的方法,研究了NiFe薄膜的厚度、溅射功率密度、溅射气压等制备工艺参数对条纹磁畴结构、面内静态磁各向异性、面内转动磁各向异性、垂直磁各向异性的影响规律.研究发现,在功率密度15.6 W/cm~2与溅射气压2 mTorr(1 Torr=1.33322×102Pa)下生长的NiFe薄膜,表现出条纹磁畴的临界厚度在250 nm到300 nm之间.厚度为300 nm的薄膜比250 nm薄膜的垂直磁各向异性场增大近一倍,从而磁矩偏离膜面形成条纹磁畴结构,并表现出面内转动磁各向异性.高溅射功率密度可以降低薄膜出现条纹磁畴的临界厚度.在相同功率密度15.6 W/cm~2下生长300 nm的NiFe薄膜,随着溅射气压由2 mTorr增大到9 mTorr,NiFe薄膜的垂直磁各向异性场逐渐由1247.8 Oe(1 Oe=79.5775 A/m)增大到3248.0 Oe,面内转动磁各向异性场由72.5 Oe增大到141.9 Oe,条纹磁畴周期从0.53μm单调减小到0.24μm.NiFe薄膜的断面结构表明柱状晶的形成是表现出条纹磁畴结构的本质原因,高功率密度下低溅射气压有利于柱状晶结构的形成,表现出规整的条纹磁畴结构,高溅射气压会导致柱状晶纤细化,面内转动磁各向异性与面外垂直磁各向异性增强,条纹磁畴结构变得混乱. 相似文献
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Andreas Kaidatzis Vassilis Psycharis Georgios Giannopoulos José Miguel García‐Martín Dimitrios Niarchos 《固体物理学:研究快报》2017,11(2)
Ultrathin FePt films (thickness between 1 nm and 5 nm) were studied for non‐volatile memories applications. The films were magnetron sputtered on monocrystalline MgO?001? substrates at 500 °C. The films are polycrystalline, except the 1 nm thick film which is not continuous. It is shown that films with thickness higher than 2.7 nm have L10 structure and perpendicular magnetic anisotropy, while a transition to in‐plane anisotropy occurs for thinner films. The out‐of‐plane coercivity drops from 16 kOe at the thicker film to 0.5 kOe at the thinner one.
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A new type of phase-shifting interferometer was presented by rotating an azo-polymer film with photo-induced optical anisotropy in the light path of orthogonal polarization interferometry. By changing the angle of the optical axis of the azo-polymer film, four phase-shifted fringe patterns were obtained, from which phase difference between orthogonal polarized light could be calculated. The polarization states and the formation of the interferograms were analyzed theoretically using Jones matrix calculations and the experimental verification of the proposed method was also given. This method has a simple optical configuration which utilizes commercially available polarization devices and anisotropic azo-polymer film of low cost. The phase-shifting interferometer also demonstrates a new application of azo-polymer film. 相似文献
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Hongyang Zhao Hideo Kimura Zhenxiang Cheng Xiaolin Wang Kiyoshi Ozawa Takashi Nishida 《固体物理学:研究快报》2010,4(11):314-316
Single phase Bi2FeMnO6 films on (100) SrTiO3 substrate were fabricated using a pulsed laser deposition method through optimization of the preparation conditions. The magnetic moment is 0.30μB at 5 K in the magnetic field of 1 T, indicating that B site cations of Fe and Mn are disordered in the sample. The zero‐field‐cooling (ZFC) and field‐cooling (FC) magnetization curves measured from 2 K to 400 K coincide at 360 K. This is consistent with the observation that hysteresis disappears at 360 K, revealing the antiferromagnetic transition at this temperature. A spin‐glass‐like behaviour was observed at low temperature (~100 K) with a cusp of 25 K. Mn shows multiple valence states in the film. It is possibly because Mn2+ and Mn4+ could decrease the Jahn–Teller effect from Mn3+ in the film which results in less lattice distortion. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Amplitude modulated Kelvin probe force microscopy was performed on molybdenum (Mo)-thin films deposited on Si(001) substrates by RF magnetron sputtering. Evolution of film microstructure from amorphous to crystalline was observed with increasing RF power from 25 W to 200 W. Spatial mapping of work function across the film surface revealed that the Mo-thin film deposited at 200 W possesses an average work function ~4.94 ± 0.06 eV while higher values were observed at lower RF powers. The genesis of distinct periodic changes in work function is attributed to the formation of the surface dipole layer associated with the adsorbates of different polarities (O2−/OH− or H+). A phenomenological model is also presented to elucidate their effect. 相似文献
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W.Y. Zhang H. Shima M. Takenaka K. Masuda T. Nagahama 《Journal of magnetism and magnetic materials》2010,322(8):900-908
In this study, the deposition pressure dependence of the compositional ratio, magnetic domain structure, and perpendicular magnetic anisotropy (PMA) of B-containing PrFe- and PrCo-based films, which are rare-earth-transition-metal (RE-TM) films, was investigated. PrFe- and PrCo-based films were fabricated by magnetron sputtering. The film compositions were controlled in a wide range by varying the deposition pressure. On the basis of experimental results, the residual stress of the films was considered to be the possible origin of their PMA. The films showed strong magneto-optical effects over the entire wavelength range of 300-750 nm. Because of the excellent magnetic and magneto-optical (MO) properties of the films, they have high potential for MO applications at wavelengths of red and blue lasers. 相似文献
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F. Yang W.B. Cui X.G. Zhao Z.D. Zhang 《Journal of magnetism and magnetic materials》2009,321(8):1068-1071
The influence of a Mn layer on the magnetic properties of sputtered Pr-Fe-B/Mn films with Cu spacer layer has been investigated for various Mn layer thicknesses. The Pr-Fe-B/Mn films all possess perpendicular anisotropy. An enhancement of the intrinsic coercivity iHc is observed for suitable Mn layer thickness and iHc exhibits an oscillatory dependence on the thickness of the Mn layer with a period of about 60 nm. The average size of the columnar Pr2Fe14B grains is about 100 nm. A highest iHc value of 22.1 kOe and an optimal (BH)max value of 18.2 MGOe are reported for these Pr-Fe-B/Mn films. 相似文献
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A lock-in amplifier detection method for measuring the film thickness on a flat substrate has been developed by using a common-path interferometer. The signal due to the film thickness has been obtained without it being affected by the tilting of the substrate. The sensitivity was better than 0.5 nm. 相似文献
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Enhancement of ferromagnetic resonance in Al_2O_3-doped Co_2FeAl Heusler alloy film prepared by oblique sputtering 下载免费PDF全文
Large and variable in-plane uniaxial magnetic anisotropy in a nanocrystalline(Co2FeAl)97.8(Al2O3)2.2soft magnetic thin film is obtained by an oblique sputtering method without being induced by magnetic field or post annealing. The in-plane uniaxial magnetic anisotropy varies from 50 Oe to 180 Oe(1 Oe = 79.5775 A·m-1) by adjusting the sample’s position. As a result, the ferromagnetic resonance frequency of the film increases from 1.9 GHz to 3.75 GHz. 相似文献