Ho2Co17—xSix化合物的结构与磁性研究

研究了非磁性原子Ｓｉ 替代Ｃｏ 对Ｈｏ２Ｃｏ１７ 金属间化合物结构和磁性的影响－Ｘ 射线衍射表明,所有Ｈｏ２Ｃｏ１７ － ｘＳｉｘ（ｘ ＝ ０ ．５ ,１ ．０ ,１ ．５ ,２ ．０ ,２ ．５ ,３ ．０） 化合物都为Ｔｈ２Ｎｉ１７ 型六角结构;化合物的晶格常数和单胞体积都随Ｓｉ 含量的增加而线性降低－ 磁性测量表明,Ｈｏ２Ｃｏ１７ － ｘＳｉｘ 化合物的居里温度和饱和磁化强度随Ｓｉ 含量的增加而线性下降－ 对Ｈｏ２Ｃｏ１７ － ｘＳｉｘ 化合物,测量了补偿点温度下的磁化曲线－ 从热磁曲线测量观察到,Ｈｏ２Ｃｏ１７ － ｘＳｉｘ 化合物在ｘ ＝ ０ ．５ 时化合物呈面各向异性,当１ ．０ ≤ｘ ≤３ ．０ 时出现由易面到易轴的自旋重取向,自旋重取向温度Ｔｓｒ 随Ｓｉ 原子含量ｘ 的增加先下降,而后又上升,在ｘ ＝ ２ ．５ 处出现最低点     

RTiFe_(11)Nx金属间化合物的结构和磁性

采用热处理的方法,使氮原子进入到 RTiFe_(11)(R=Y,Nd,Sm)的结构中去.利用 x 射线衍射和磁测量研究了 RTiFe_(11)N_x 的晶体结构和内禀磁性.x 射线衍射表明 RTiFe_(11)N_x 仍保持 RTiFe_(11)的四方结构(I4/mmm).氮原子的加入使晶胞体织增大,Curie 温度升高,改变了磁晶各向异性.在 RTiFe_(11)N_x 化合物中,NdTiFe_(11)N_x的饱和磁化强度高,Curie 温度高,有高单轴磁晶各向异性.这些效应使 NdTiFe_(11)N_x具备了研制高矫顽力永磁体的潜力.     

激光辐照Z10硅钢片的磁性能研究

本文对激光辐照的软磁材料—Z10硅钢片进行了细致的磁性能的研究。通过不同激光辐照功率密度处理样品的磁测量,结果表明材料的各向异性常效K_1有所减小。特别是随着激光功率密度的增加,材料的磁性参数发生了变化。这将进一步证实了激光辐照对材料磁性的影响。     

Cex(Tb0.27Dy 0.73)1-xFe2合金的结构与磁致伸缩

采用X射线、金相和应变测试技术研究了Cex(Tb0.27Dy 0.73)1-xFe2合金的显微结构、晶格常数及磁致伸缩,结果表明未退火合金的主相为MgCu2型立方结构的1∶2相,第二相为1∶3相,且随着Ce含量的增加,第二相的含量也逐渐增加.经过700 ℃,72 h退火后,第二相的含量明显减少.合金的晶格常数和磁致伸缩随Ce含量的增加而减小.     

Cex(Tb0.27Dy0.73)1-xFe2合金的结构与磁致伸缩

采用X射线、金相和应变测试技术研究了Cex(Tb0.27Dy 0.73)1-xFe2合金的显微结构、晶格常数及磁致伸缩,结果表明未退火合金的主相为MgCu2型立方结构的1∶2相,第二相为1∶3相,且随着Ce含量的增加,第二相的含量也逐渐增加.经过700 ℃,72 h退火后,第二相的含量明显减少.合金的晶格常数和磁致伸缩随Ce含量的增加而减小.     

机械合金化Fe74.5Nb3Si13.5B9合金微观结构及磁性能

研究了Fe74.5Nb3Si13.5B9的机械合合金化过程，并对其机械合金化的机制进行了探讨，研究表明Fe74.5Nb3Si13.5B9经高能球磨20h可形成α-Fe固溶体纳米晶合金，球磨100h，纳米晶粒的平均尺寸为10nm左右，同时机械合金化使这些元素在铁中的固溶度在一定程度上得到了扩展。该合金的磁性能测定表明，其比饱和磁化强度和矫顽力分别达到了77.87Am^2/kg和125.6A/m.     

场致排列CrO2/Polystyrence复合材料结构及磁性分析

研究了CrO2/Polystyrence（聚苯乙烯简称PS）的场致排列复合材料的结构与磁性.通过对场致排列CrO2/PS复合样品与随机样品XRD的比较分析显示复合排列样品具有明显的各向异性特征,PS的加入并没有改变晶体的结构.磁滞洄线分析显示磁场平行于样品的易磁化轴时样品的磁矩很容易饱且剩磁较大,垂直时样品的磁矩不容易饱且剩磁较小.     

晶化处理对Nd9Fe85B6磁性能的影响

为了研究晶化处理对Nd9Fe85B6纳米双相永磁材料磁性能的影响．利用三种不同晶化处理工艺对Nd9Fe85B6磁性材料进行晶化处理，并对其磁性能进行了测试．测试结果表明晶化处理工艺的温度、时间不同将影响Nd9Fe85B6纳米双相永磁材料的磁性能，初步探索的晶化工艺为晶化温度在780℃左右，时间在6min左右时所得的磁性能较好．     

Sn对烧结钕铁硼合金磁性能的影响

研究了Ｓｎ含量对烧结三元ＮｄＦｅＢ合金、ＮｄＤｙＦｅＡｌＢ合金磁性能的影响,Ｓｎ采用辅合金引入,研究发现Ｓｎ使三元ＮｄＦｅＢ磁性能全面降低,且随含Ｓｎ量增加、下降幅度增大,而对于ＮｄＤｙＦｅＡｌＢ合金,在适当热处理情况下,添加Ｓｎ使合金的矫顽力者到提高,最佳含Ｓｎ量约为０．１５％（质量分数）,但是,不适当的热处理,使ＮｄＤｙＦｅＡｌＢＳｎ合金的矫顽力反应而比热处理前还低,Ｘ射线衍射实验表明,顽力下降的合金中出现明显的α－Ｆｅ衍射峰,模型计算也说明,吹磁性α－Ｆｅ的析出是合金顽力下降的原因。     

Co掺杂浓度对SiC薄膜磁性能的影响

为了研究掺杂元素Co对SiC薄膜磁性影响,采用磁控溅射技术制备了不同Co含量的SiC薄膜。采用XRD、X光电子能谱和理性质测试系统对薄膜结构、成分和磁性进行表征。分析表明,薄膜具有3C-SiC晶体结构,随着掺杂元素Co增加,3C-SiC晶体特征峰向小角度移动。掺杂元素以Co~(2+)形式存在,形成CoSi第二相化合物,随着Co掺杂浓度增加,CoSi第二相化合物含量增多。磁性测试显示,掺有Co元素的SiC薄膜在室温下具有铁磁性,随着Co含量增加,薄膜的饱和磁化强度先增大后减小。掺杂Co原子进入SiC晶格后形成的缺陷是产生薄膜磁性的原因,属于掺杂缺陷诱导产生的铁磁性,而第二相化合物CoSi抑制了薄膜的铁磁性。     

Influence of modulated structure on magnetic properties of NdFeB/Co multilayer thin films

The Nd Fe B/Co multilayer films were prepared by magnetron sputtering. After that, the samples were annealed at 600 °C for 20 min. The surface morphology, phase structures and magnetic properties of Mo(50 nm)/[Nd Fe B(100 nm)/Co(y)]×10/Mo(50 nm) thin films were researched by AFM, XRD and VSM, respectively. The results show that the films show stronger perpendicular magnetic anisotropy. When the thickness of Co layers is 10 nm, the coercivity Hc⊥ is the maximum, 295 k A/m. However, for y=10-20, the reduced remanence M/Ms of films has increased. When the thickness of Co layers is 20-30 nm, the Nd Fe B/Co multilayer films obtained more superior magnetic properties with M/Ms =0.95.     

Preparation and magnetic properties of Co-P thin films

Magnetic Co-P thin films were prepared by electroless deposition. The experiment results show that the film thickness has a significant influence on the coercivity. While the film thickness varied from 300 nm to 5 μm,the coercivity dropped sharply from 45.36 to 22.28 kA/m. As the film thickness increased further,the coercivity varied slowly. When the thickness of the film was 300 nm,the deposited film could realize the coercivity as high as 45.36 kA/m,and the remanent magnetization as high as 800 kA/m .The ...     

Microwave magnetic properties of laminates with thin FeCoBSi films

The microwave permeability of laminated composites based on thin FeCoBSi films was under study.The level of permeability increased with increasing of the ferromagnetic inclusions in the laminates.The intrinsic permeability spectra of ferromagnetic inclusion are parametrically reconstructed.The obtained parameters of magnetic resonance were specially analyzed.To avoid the effect of eddy current and to obtain large-volume fractions of ferromagnetic constituent,laminates consisting of alternating FeCoBSi/SiO2 multi-layers and mylar substrates were also investigated.For the same volume fractions of ferromagnetic constituent (8.7%),laminates based on multi-layered films are found to possess higher values of permeability than those based on one-layered films.     

Fe-N合金的结构和磁性

为开发新结构的磁性材料,采用机械球磨Fe和六方氮化硼(h-BN)混合粉末形成了Fe-N非晶合金和纳米晶合金.利用Mossbauer谱仪、X-射线衍射分析和振动样品磁强计研究了球磨参量对合金的形成机制和结构转变的影响.结果表明:随球磨时间的增加,首先形成非晶Fe-N合金,然后晶化成六方结构的ε-FexN合金,Fe-N合金晶化时还发生了电子相变.表征了Fe-N非晶和ε-FexN合金的磁性,得到ε-FexN合金磁性能随N含量的增加从铁磁转变为顺磁的变化规律,阐明了样品的饱和磁感应强度随球磨时间变化的规律和机制.可见采用六方氮化硼为氮源、高能球磨制作Fe-N合金是一种有效方法.     

FePt/Ag薄膜的结构和磁性

采用直流磁控溅射在SiO2〈0001〉基片上制备了FeAg和FePt/Ag薄膜,将其在不同温度下进行真空热处理,得到具有高矫顽力的L10-FePt颗粒膜。利用X射线衍射、振动样品磁强计、扫描探针显微镜对样品的结构、磁性、形貌进行了研究。结果表明:Ag元素的添加有效地降低了FePt薄膜的有序化温度,样品在300℃热处理时即发生有序化转变。随着热处理温度的升高,样品的有序化程度提高,矫顽力变大,样品表面粗糙度减小,形成了均匀的颗粒薄膜。     

Perpendicular magnetic anisotropy of Co85Cr15/Pt multilayers

The CoCr/Pt bilayers and (CoCr/Pt)20 multilayers with Pt underlayer were prepared by DC magnetron sputtering. The effects of prepared condition on perpendicular magnetic anisotropy were investigated. The results show that the thickness of Pt underlayer has a great effect on the microstructure and perpendicular magnetic anisotropy of CoCr/Pt bilayers and (CoCr/Pt)20 multilayers.When the thickness of Pt underlayer increases, Pt(111) and CoCr(002) peaks of both CoCr/Pt bilayers and (CoCr/Pt)20 multilayers increase and the bilayer periodicity of the multilayers is improved. The effective magnetic anisotropy of (CoCr/Pt)20 multilayers with Pt underlayer was much larger than that of CoCr/Pt bilayers. The (CoCr/Pt)20 multilayers has a stronger perpendicular magnetic anisotropy than that of CoCr/Pt bilayers. This is ascribed to the interface magnetic anisotropy of the multilayers.     

Effect of Sm-doping on the morphology and magnetic properties of radio frequency magnetron sputtered Ni-Mn-Ga films

Ni55.5Mn21Ga23.5 and Ni54Mn22Ga23Sm1 films were prepared by radio frequency (RF) magnetron sputtering. The effect of Sm do-pant on the morphologic and magnetic properties of Ni55.5Mn21Ga23.5 films was investigated. Sm doping can refine the particle size of the films from 100 to 60 nm, and further grain growth is not occurs even after annealing at 1073 K for 3.6 ks. Compared to Ni55.5Mn21Ga23.5 films, Sm-doped Ni54Mn22Ga23Sm1 films are easier to be magnetized and have a lower martensitic transformation temperature. In addition, the Curie temperature can also be adjusted, decreasing from 350 to 325 K after Sm doping. Martensitic transformation is not observed in the Sm-free films, which is close to the Curie temperature in the Sm-doped films, giving rise to the overlap of the structural and magnetic transi-tion temperatures.     

Pr1(Co40Ag60)99颗粒膜的结构和电磁性能

用磁控溅射方法制备了Pr1(Co40Ag60)99颗粒膜样品并对其结构和电磁性能进行了研究.X-射线衍射结果表明:随着退火温度的升高,颗粒膜中的晶粒逐渐聚集长大,Ag聚集长大存在择优取向.四探针测量结果显示:巨磁电阻效应(GMR)随着退火温度的升高逐渐减小,且在低场下(小于1.5×105A/m)对磁场的灵敏度增大.颗粒的聚集长大导致GMR逐渐减小,说明磁性颗粒的大小对GMR的影响是成反比的.磁性测量表明颗粒膜的磁性为顺磁性,应用朗之万函数拟合磁化曲线计算了沉积态磁性颗粒尺寸.