衬底层对Fe65Co35合金薄膜结构与磁性的影响

采用磁控溅射法制备了具有不同衬底层(Cu, Co和Ni₈₀Fe₂₀)的FeFe₆₅Co₃₅双层合金薄膜.研究了不同衬底材料以及NiFe衬底层厚度对FeCo合金薄膜结构与磁性的影响.研究结果表明:衬底层的引入可以增加薄膜的面内单轴各向异性,且薄膜的软磁性能显著提升,获得良好软磁性的原因归结为晶粒的细化、层间的偶极相互作用以及表面粗糙度的降低,并且对于相同厚度的不同衬底层, NiFe衬底层对FeCo薄膜软磁性能的提升最为明显;通过改变NiFe衬底层厚度,实现了对薄膜各向异性的调控, NiFe/FeCo表现出良好的高频响应和低的阻尼系数,同时较小的薄膜厚度能够减小涡流损耗,因此,促进了其在高频微波磁性器件方面的应用.     

纳米结构SmCo/FeCo多层薄膜的磁性

研究了用磁控溅射方法制备的纳米结构Sm₂₂Co₇₈单层膜、Sm₂₂Co₇₈/Fe₆₅Co₃₅双层膜及Sm₂₂Co₇₈/Fe₆₅Co₃₅/Sm₂₂Co₇₈三层膜的磁性,特别是双层膜及三层膜系统中的Fe₆₅Co₃₅软磁层厚度d对薄膜剩磁比(M_r/M_s)和矫顽力(H_c)的影响.所有样品的磁滞回线测量表明,该系列薄膜的易磁化轴在膜面内.磁滞回线的单一硬磁相特征,说明SmCo硬磁层与FeCo软磁层之间的交换相互作用使两相很好地复合在一起.在双层膜和三层膜中,M_r/M_s随软磁层厚度d的增加单调上升,而矫顽力随d的变化出现一峰值.通过研究ΔM随磁场H的变化,发现随着软、硬磁相界面数的增加,ΔM曲线的正峰数量逐渐减少;负峰数量逐渐增强,负峰的半高宽逐渐减少. 关键词：     

Nd-Fe-B/FeCo多层纳米复合膜的结构和磁性

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(t_FeCo=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t_FeCo=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     

Nd28Fe66B6/Fe50Co50双层纳米复合膜的结构和磁性

利用磁控溅射法制备了Nd₂₈Fe₆₆B₆/Fe_{50Co50 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160×１０^３A/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}     

Fe15.38Co61.52Cu0.6Nb2.5Si11B9纳米晶软磁合金的交流磁性

研究了退火温度对Fe_15.38Co_61.52Cu_0.6Nb_2.5Si₁₁B₉纳米晶软磁合金交流磁性的影响,并且分析了获得较好软磁性能的可能原因.合金的电阻率随着退火温度的增加逐渐降低.μ'f0值与饱和磁化强度M_s之间没有明显的正比关系,合金的旋磁比γ随退火温度的升高应呈不规则的 关键词： 纳米晶合金 软磁材料 品质因数 热处理     

熔体快淬Pr(Fe1-xCox)2合金的结构和磁性

通过熔体快淬方法获得Pr(Fe_1-xCo_x)₂合金条带,经过X射线衍射、差示扫描量热计和磁性测量对其结构、磁性和热稳定性进行了研究.发现当Co的含量x大于0.2时才可能获得Pr(Fe,Co)₂立方Laves相化合物.对Pr(Fe_0.6Co_0.4)₂合金,在快淬速度为30m/s时,条带由Pr₂(Fe,Co)₁₇,Pr(Fe,Co)₂和富稀土相组成;在速度为40m/s时,获得了几乎单相的Pr(Fe_0.6Co_0.4)₂化合物,其居里温度为305℃;在速度为45m/s时,除了Pr(Fe_0.6Co_0.4)₂化合物外,还存在少量的非晶相.Pr(Fe_0.6Co_0.4)₂化合物在770℃以上发生分解.用40m/s快淬纳米晶粉胶粘磁体有大的磁致伸缩系数（λ_∥-λ_⊥=140×10^-6)和高的硬磁性能（_iH_c=398kA/m). 关键词：     

择优取向MgO缓冲层上制备的硅基Ba0.7Sr0.3TiO3薄膜的结构和性能研究

分别采用sol-gel法和磁控溅射法在Si（001）单晶衬底上制备出（111）和（001）取向的MgO缓冲层薄膜,随后在其上生长Ba_0.7Sr_0.3TiO₃（BST30）铁电薄膜.通过X射线衍射,扫描电子显微镜,原子力显微镜等方法研究了薄膜的微结构.实验结果发现,在较厚的MgO（001）缓冲层上可长出（101）取向的BST30薄膜,而在较薄的MgO（111） 缓冲层上则表现出（101）和（111）取向相互竞争的现象,随着MgO（111）缓冲 关键词： 0.7Sr_0.3TiO₃')" href="#">Ba_0.7Sr_0.3TiO₃ 铁电薄膜 择优取向 sol-gel     

真空退火对周期性界面掺杂Ni80Co20薄膜磁性的影响

用磁控溅射方法制备了两个具有不同Fe层厚度的［Ni₈₀Co₂₀(L)/Fe(t_Fe)］_N多层膜系列样品,其中t_Fe=0.1和2nm.研究了两个系列样品的磁及输运性质随Ni₈₀Co₂₀层厚度L的变化关系.在退火态［Ni₈₀Co₂₀(L)/Fe(0.1nm)］_N系列样品中,发现各向异性磁电阻( 关键词： 多层膜 各向异性磁电阻 界面效应 退火     

Pb(Zr0.3Ti0.7)O3铁电薄膜激光感生电压效应

采用脉冲激光沉积(PLD)技术在LaSrAlTaO₃(LSATO),LaAlO₃(LAO)和SrTiO₃(STO)的单晶倾斜衬底上成功制备了Pb(Zr_0.3Ti_0.7)O₃(PZT)薄膜,在三种倾斜衬底上生长的PZT薄膜中都首次发现了LIV效应.对PZT/LSATO薄膜在a,c轴两种不同取向择优生长下的LIV效应做了研究,发现在薄膜c轴取向择优生长 关键词： 激光感生电压效应 铁电薄膜 薄膜生长取向 原子层热电堆     

2: 17型结构Gd-Fe-Co-Ga化合物的结构与磁性

用电弧熔炼的方法制备了Gd₂（Fe_1-xCo_x）₁₅Ga₂（0≤x≤1.0）和Gd₂（Fe_0.8Co_0.2）_17-yGa_y（0≤y≤8）化合物，通过Ｘ射线衍射和磁性测量手段研究了它们的结构和磁性．实验结果表明它们都是2∶17型结构的单相化合物．Gd₂（Fe_{1 关键词：}     

Effects of underlayer materials and substrate temperatures on the structural and magnetic properties of Nd2Fe14B films

Thin films of Nd_2Fe_{14}B were fabricated on heated glass substrates by dc magnetron sputtering. Different material underlayers (Ta, Mo, or W) were used to examine the underlayer influence on the structural and magnetic properties of the NdFeB films. Deposited on a Ta buffer layer at 420℃, the 300 nm thick NdFeB films were shown to be isotropic. But when the substrate temperature T_s was elevated to 520℃, the Nd_2Fe_{14}B crystallites of (00l) plane were epitaxially grown on Ta (110) underlayer. In contrast, Mo (110) buffer layer could not induce any preferential orientation in NdFeB film irrespective of the substrate temperature or film thickness. The W buffer layer was found to be most effective for the nucleation of Nd_2Fe_{14}B crystallites with c-axis alignment perpendicular to the film plane when T_s<490℃. But at T_s=490℃ the magnetic layer became isotropic. The maximum coercivity obtained was about 995 kA/m for the 100nm film deposited on W underlayer at 490℃. These variations were tentatively explained in terms of the lattice misfit between the underlayer and the magnetic layer, combined with the considerations of underlayer morphologies.     

采用PVA方法制备ZnO基发光稀磁半导体

不同的制备工艺对ZnO薄膜的微结构和性能有很大的影响,为了得到成本较低,样品具有较好特性的实验方法,对于制备手段进行了探索。使用PVA溶胶-凝胶法制备了Zn_0.88Co_0.12O薄膜,研究了不同退火工艺对其微结构的影响。对于Zn_0.88Co_0.12O样品的微结构和室温下的铁磁性和发光特性,具体比较分析了产生原因。对比了Co掺杂和复合Co、Fe掺杂Zn_0.88(Co_0.5Fe_0.5)_0.12O样品的微结构,采用振动样品磁强计(VSM)测量了样品的磁特性,发现单一掺杂的薄膜具有更好的晶体质量和更强的磁性。     

Sm–Co and Nd–Fe–B thin films with perpendicular anisotropy for high-density magnetic recording media

Sm–Co and Nd–Fe-B thin films have been prepared by sputtering. Particular efforts are concentrated on the perpendicular texture growth of the films. The Sm–Co and Nd–Fe–B thin films with perpendicular magnetic anisotropy can be prepared on Cu and W underlayer, respectively. Those underlayers play an important role to prevent oxidation and improve crystal lattice orientation. Perpendicular coercivity and remanent squareness ratio are higher than 10 kOe and almost 1.0, respectively, in both films prepared under optimum conditions.     

Sm3（F3,Co,Mn）29 compounds：promising materials for permanent magnets

The outstanding hard-magnetic properties are reported of Sm_3Fe_{28.1-x}Co_xMo_{0.9} compounds with x=12, 14, 16. In this alloy system, only a small amount of Mo is needed to stabilize the 3:29 structure so that the magnetic properties are not seriously affected by the presence of this nonmagnetic element. Substitution of Co for Fe leads to a significant increase of the magnetic anisotropy, and for x≥14 the easy magnetization direction changes from easy plane to the easy axis. In this alloy system, the compound Sm_3Fe_{12.1}Co_{16}Mo_{0.9} is a very promising candidate for permanent magnet applications. Its room temperature saturation magnetization (μ_0M_s=1.5 T) and anisotropy field (B_{an}=6.5 T) are comparable to the values for Nd_2Fe_{14}B (μ_0M_s=1.6 T and B_{an}=7 T). However, the Curie temperature of Sm_3Fe_{12.1}Co_{16}Mo_{0.9} is 1020 K, which is appreciably higher than that for Nd_2Fe_{14}B (T_C=588 K).     

Influence of the working gas pressure on the magnetic properties and texture of magnetron-sputtered Fe/SiO<Subscript>2</Subscript>/Si(100) polycrystalline films

The magnetic properties and texture of 90-nm-thick polycrystalline Fe/SiO₂/Si(100) films magnetron-sputtered under different working gas pressures are investigated. It is shown that when the pressure declines, the magnetization of the films may grow by 50%, whereas the ferromagnetic resonance linewidth and the coercive force may decrease by more than an order of magnitude. Such variations of the magnetic properties correlate with a Fe(110) to Fe(200) change in the film texture and with the columnar to quasi-uniform microstructure transition.     

Tunable magnetic properties of arrays of Fe(1 1 0) nanowires grown on kinetically grooved W(1 1 0) self-organized templates

We report a detailed magnetic study of a new type of self-organized nanowires discussed briefly previously [B. Borca et al., Appl. Phys. Lett. 90 (2007) 142507]. The templates, prepared on sapphire wafers in a kinetically limited regime, consist of uniaxially grooved W(1 1 0) surfaces, with a lateral period here tuned to 15 nm. Fe deposition leads to the formation of (1 1 0) 7 nm-wide wires located at the bottom of the grooves. The effect of capping layers (Mo, Pd, Au, Al) and underlayers (Mo, W) on the magnetic anisotropy of the wires was studied. Significant discrepancies with figures known for thin flat films are evidenced and discussed in terms of step anisotropy and strain-dependent surface anisotropy. Demagnetizing coefficients of cylinders with a triangular isosceles cross-section have also been calculated, to estimate the contribution of dipolar anisotropy. Finally, the dependence of magnetic anisotropy with the interface element was used to tune the blocking temperature of the wires, here from 50 to 200 K.     

Magnetic and structural properties of Fe(110)/Ag(111) and Fe(100)/Ag(100) multilayers

A comparison of the magnetic and structural properties and growth characteristics between Fe(110)/Ag(111) and Fe(100)/Ag(100) multilayers is presented. The two types of multilayers were made of the same constituent materials but with different oricutations, allowing us to examine the interesting interplay between structure and magnetism. We found fundamentally different magnetic properties including magnetocrystalline anisotropy and surface/interface and thin film magnetism for the two types of multilayers, and their origins were discussed. Presently at the Naval Research Laboratory. Presently at Argonne National Laboratory.     

衬底对Cu(In,Ga)Se2薄膜织构的影响

分别在苏打石灰玻璃、Mo箔、无择优取向的Mo薄膜以及(110)择优取向的Mo薄膜四种不同衬底上，采用共蒸发工艺沉积约2 μm厚的Cu(In,Ga)Se₂薄膜，用X射线衍射仪测量薄膜的织构，研究衬底对Cu(In,Ga)Se₂薄膜织构的影响.在以上四种衬底上沉积的Cu(In,Ga)Se₂薄膜的(112)衍射峰强度依次逐渐减弱，(220/204)衍射峰从无到有且强度逐渐增强.在苏打石灰玻璃和Mo箔衬底上的Cu(In,Ga)Se_{2关键词： 择优取向 Cu(In 2}薄膜')" href="#">Ga)Se₂薄膜 太阳电池     

Er3(Fe,Co, M)29化合物(M=Cr,V, Ti,Mn, Ga,Nb)的结构与磁性

合成了Er_３Fe_29-x-yCo_xM_y化合物(M=Cr, V, Ti, Mn, Ga, Nb )并用x射线衍射和磁测量等手段研究了它们的结构和磁性. 发现Fe基Er_３(Fe,M)_２９化合物结晶成哑铃对Fe-Fe无序替代的Th₂Ni₁₇型结构(P6₃/mmc空间群)而不能形成Nd₃(Fe,Ti)_２９型结构，因此其化学式也可以用Er_2－n(Fe,M)_17+2n (n=0.2)表示. 当Er_３Fe₂₉化合物中部分Fe原子被M原子所取代时，其居里温度均有一定程度的提高. 所有Er_３(Fe,M)_２９化合物在室温均为易面型各向异性. 当Er_３(Fe,M)_２９ (M=Cr, V)中的部分Fe原子被Co原子取代且Co原子数与Fe原子数达到一定比值时，得到一个单斜结构的新相. 磁测量表明Er_３Fe_19.5Co₆V_3.5在室温可能为单轴各向异性，在162K出现自旋重取向，其各向异性由易轴型变为易面型. 在5K下于难磁化方向磁化时观察到一个一级磁化过程(FOMP). 关键词： 稀土金属间化合物 晶体结构 磁晶各向异性     

Remanence Enhancement Effect in Ni_(0.7)Zn_(0.3)Fe_2O_4/Co_(0.8)Fe_(2.2)O_4 Ferrite Multilayer Film

Ni_(0.7)Zn_(0.3)Fe_2O_4/Co_(0.8)Fe_(2.2)O_4(NZFO/CFO) multilayer films are fabricated on Si(100) substrates by the chemical solution deposition method.The microstructure and magnetic properties are systematically investigated.The results of field-emission scanning electronic microscopy show that the grain size of the NZFO/CFO multilayer film is quite uniform and the thickness is about 300 nm.The remanence enhancement effect of the NZFO/CFO multilayer film can be mainly attributed to the exchange coupling interaction between NZFO and CFO ferrite films,which is in favor of the design and fabrication of modern electronic devices.