Magnetic and magnetooptical properties of Fe/Pt and Fe/Pt/Fe thin-film magnetic structures

Results of a study of magnetic and magnetooptical properties of Fe/Pt double-layer and Fe/Pt/Fe three-layer thin-film magnetic structures are presented. A strong effect of the Pt layer on magnetic properties of the studied samples was revealed. It was established that the saturation field of three-layer magnetic structures has an oscillating magnitude with varying Pt layer thickness, and the oscillation period is a function of the Fe layer thickness. The data obtained are explained by the presence of exchange interaction between the Fe layers via the Pt layer. A strong effect of Pt on spectral dependences of the equatorial Kerr effect in the thin-film structures under study is revealed.     

Intensity enhanced bulk photovoltaic effects in LiNbO3:Fe

The use of various methods processing Doppler broadened annihilation spectra taking into account the detector resolution function and the restoration of the electronpossitron pair momentum distribution is discussed. A statistic regularisation method is proposed. The method is found to be effective particularly for the study of electron momentum distribution in metals.     

Finite size effects with variable range exchange coupling in thin-film Pd/Fe/Pd trilayers

The magnetic properties of thin-film Pd/Fe/Pd trilayers in which an embedded - thick ultrathin layer of Fe induces ferromagnetism in the surrounding Pd have been investigated. The thickness of the ferromagnetic trilayer is controlled by varying the thickness of the top Pd layer over a range from 8 to . As the thickness of the top Pd layer decreases, or equivalently as the embedded Fe layer moves closer to the top surface, the saturated magnetization normalized to area and the Curie temperature decreases, whereas the coercivity increases. These thickness-dependent observations for proximity-polarized thin-film Pd are qualitatively consistent with finite size effects that are well known for regular thin-film ferromagnets. The critical exponent β of the order parameter (magnetization) is found to approach the mean field value of 0.5 as the thickness of the top Pd layer increases. The functional forms for the thickness dependences, which are strongly modified by the nonuniform exchange interaction in the polarized Pd, provide important new insights to understand nanomagnetism in two-dimensions.     

微合金化元素对Fe-Al界面结合的第一性原理研究

利用第一性原理中的DFT理论研究了Fe/Al界面的能量学和电子结构,讨论了替位型掺杂的元素Zn、Mn、Ni在Fe/Al界面处的作用.结果表明:元素Zn、Mn、Ni都会优先替换界面处的Fe原子,使得界面结合能增加,体系更稳定,有利于界面的结合;跨界面的Fe原子与Al原子之间的电荷布居、键长以及差分电荷密度图的计算表明:掺杂后有利于跨界面的Fe-Al间成键,从而加强了Al层与Fe基体的结合,且结合强度由强到弱依次为:掺Zn>掺Mn>掺Ni;与实验比较吻合.最后对掺杂Zn的增韧机理加以解释.     

The effect of a nonmagnetic Zr layer on the magnetic and magneto-optical properties of Fe/Zr and Fe/Zr/Fe thin-film systems

The magnetic and magneto-optical properties of nanocrystalline Fe/Zr and Fe/Zr/Fe thin-film systems have been studied using the magneto-optical method. The strong effect of Zr layer thickness t _Zr on the magnetic properties of Fe/Zr samples was discovered. It was found that the value of the saturation field of the Fe/Zr/Fe systems oscillates as a function of t _Zr, which is explained by the oscillating character of the exchange interaction between ferromagnetic layers via a Zr spacer with the change in t _Zr. It was established that the values of the transverse Kerr effect depend on the thicknesses of both magnetic and nonmagnetic layers.     

Preparation and characterization of the ZnO:Al/Fe65Co35/ZnO:Al multifunctional films

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.     

永磁性Pr55Al12Fe30Cu3 大块金属玻璃

报道一个新的Pr55Al12Fe30Cu3 大块金属玻璃.采用铜模吸铸法制备了直径为5 mm、长度达100 mm的Pr55Al12Fe30Cu3 大块金属玻璃.差示扫描量热分析结果表明在该Pr基大块金属玻璃体系具有宽达64 K左右的过冷液相区，而且该合金呈非晶态时的熔化温度要比相应晶态样品的熔化温度高约140 K.磁滞回线测量表明非晶态Pr55Al12Fe30Cu3 块体合金在室温下呈现永磁特性，而完全晶化后样品在室温下呈现软磁特性. 关键词： 大块金属玻璃 玻璃转变 晶化 永磁性     

Effective optical parameters of thin-film and bulk metamaterials ofmetallodielectric nanosandwiches

We report on the effective optical response of single- and multilayer periodic structures of metallodielectric nanosandwiches on the basis of rigorous, full-electrodynamic calculations by the extended layer-multiple-scattering method. It is shown that the complex photonic band structure and the reflection coefficient of the infinite and semi-infinite crystal, respectively, provide reliable bulk effective parameters, which can be used as a reference in order to resolve ambiguities and problems in the determination of these parameters for finite slabs by the S-matrix retrieval procedure. Our results show that the structures under consideration exhibit strong artificial optical magnetism and thin films consisting of a few layers already behave like the bulk metamaterial.     

Structural investigations of laser-deposited Fe/Al multilayers

Fe/Al multilayers are prepared by crossed-beam pulsed laser deposition and investigated by Rutherford backscattering, conversion electron M?ssbauer spectroscopy, and transmission electron microscopy. The results are compared to purely ballistic simulations of the deposition process using the TRIDYN4.0 code. It is found that the intermixing of adjacent layers must be described in terms of ballistic mixing followed by chemical mixing. The phase formation in the transition layer between adjacent layers follows the non-equilibrium behavior of Fe/Al in analogy to investigations on mechanically alloyed and ion-beam-mixed Fe/Al. In Fe-rich areas a bcc solid solution is formed. In Al-rich environment an amorphous phase is observed. Received: 13 January 1999 / Accepted: 14 January 1999 / Published online: 7 April 1999     

Amorphization of bulk TiNi-based alloys by severe plastic deformation under high pressure torsion

The structure of bulk samples of Ti_49.4Ni_50.6 alloy after severe plastic deformation by torsion (SPDT) under high pressure have been studied by transmission and scanning electron microscopies. It is found that SPDT by five to seven turns led to almost complete alloy amorphization.     

Fe/Al混合膜的PLD法制备及表面分析

 采用脉冲激光气相沉积（PLD）技术制备了Fe/Al混合膜,测量了该混合膜的光电子能谱（XPS）,并采用原子力显微镜（AFM）、扫描电子显微镜（SEM）对Fe/Al混合膜作了表面分析。结果表明：Fe/Al混合膜的表面粗糙度对衬底温度有明显的依赖性, 随着衬底温度的升高,薄膜的表面逐渐变得平滑,膜层变得致密,在200 ℃衬底温度下制得了均方根（rms）粗糙度为0.154 nm、具有原子尺度光滑性的Fe/Al混合膜, 膜中Fe和Al分布比较均匀,其成分比约为1∶3,同时XPS分析也表明Fe/Al混合膜暴露在空气中后表面形成了Al₂O₃和FeO氧化层。     

Fe/Al混合膜的PLD法制备及表面分析

采用脉冲激光气相沉积（PLD）技术制备了Fe/Al混合膜,测量了该混合膜的光电子能谱（XPS）,并采用原子力显微镜（AFM）、扫描电子显微镜（SEM）对Fe/Al混合膜作了表面分析。结果表明：Fe/Al混合膜的表面粗糙度对衬底温度有明显的依赖性, 随着衬底温度的升高,薄膜的表面逐渐变得平滑,膜层变得致密,在200 ℃衬底温度下制得了均方根（rms）粗糙度为0.154 nm、具有原子尺度光滑性的Fe/Al混合膜, 膜中Fe和Al分布比较均匀,其成分比约为1∶3,同时XPS分析也表明Fe/Al混合膜暴露在空气中后表面形成了Al2O3和FeO氧化层。     

压力下 Nd60Al10Fe20Co10块体金属玻璃的弹性行为

室温下在等静压最高达～0.5GPa的条件下,利用超声回波技术测量了超声波横波和纵波在Nd60Al10Fe20Co10块体金属玻璃中的传播时间来确定横波和纵波速度.测量时所采用的超声波频率为10MHz.利用所测量的数据,建立了超声波波速、样品的密度、弹性模量以及Debye温度等与所施加的压力之间的相互关系.并且推导出Murnaghan状态方程.另外,基于非晶态与晶态物理性能的相似性,对此块体非晶的压缩曲线、弹性常数和Debye温度等进行了理论计算,结果表明Nd60Al10Fe20Co10块体金属玻璃的弹性性能与其组成的元素有着密切的关系.     

Electron and x-ray diffraction studies on Al86Fe14, Al82Fe18 and Al75Fe25 quasicrystals

Electron and x-ray diffraction experiments on the metlt-spun Al_100−x Fe _x (x=14, 18, 25) alloys are carried out. It is observed that all the melt-spun alloys possessing the quasi-crystalline phases have icosahedral point-group symmetry. The authors felicitate Prof. D S Kothari on his eightieth birthday and dedicate this paper to him on this occasion.     

Ion beam mixing of Al/Fe binary systems

Ion beam mixing of Al layers on Fe and Fe layers on Al are studied by irradiation with 200 keV Xe⁺-ions at room temperature as a function of the thickness of the top layer and of the ion fluence from 5×10¹⁵ to 7.5×10¹⁶ions/cm². Deconvolution procedures are needed to separate the influence of the ion sputter profiling by AES from the ion beam induced mixing effects. Auger electron spectroscopy data reveal that the mixing induced diffusivity ought to be considered as a function of concentration. The diffusion coefficients are evaluated by the Boltzmann-Matano method. A strong dependence of the diffusion coefficients and also the mixing efficiencies from the ion dose, the depth of the interface and the nuclear energy deposition were observed. Results are discussed in terms of the diffusional and collisional mixing as well as chemical affinity of both Fe and Al.     

Mössbauer study of the stability of quasicrystalline phases: Al78Fe22 and Al82Fe18

A quasicrystal of Al-Fe with a stoichiometric composition very close to a crystalline phase is shown to transform to the crystalline phase with simple thermal cycling from 300 K through 78 K and 300 K.