Effect of fabrication parameters on the microstructure,in-plane anisotropy and magnetostriction of Fe-Ga thin films

The microstructure,in-plane anisotropy,and magnetic properties of Fe-Ga thin films were investigated by X-ray diffraction analysis,vibrating sample magnetometer,and capacitive cantilever method.The in-plane induced anisotropy is well formed by the applied magnetic field during sputtering,and the anisotropy field Hk decreases with the sputtering power increasing.The coercivity of Fe-Ga thin films decreases with increasing power when the sputtering power is less than 60 W and increases when the power is larger than 60 W.The magnetostriction of the thin films reaches 66 × 10-6 at the sputtering power of 60 W.Excellent Fe-Ga films,which exhibit good field sensitivity,low coercivity and high magnetostriction,have been fabricated at the power of 60 W,and they can be used as the materials of magnetostrictive transducers.     

Structural and magnetic properties of (Sm_0.5Nd_0.5)_2(Fe_(1-x)Co_x)_(17)compounds

The structure, magnetization, and magnetocrystalline anisotropy were investigated using X-ray diffraction, vibrating sample magnetometer, and AC susceptibility-meter. It is found that the microstructure of (Sm0.5Nd0.5)2(Fe1-xCox)17 alloys is an (Sm,Nd)2(Fe,Co)17 phase with the rhombohedral Th2Zn17-type structure. The Curie temperature Tc increases with the Co concentration increasing, and the magnetization first increases as the Co content increases in (Sm0.5Nd0.5)2(Fe1-xCox)17 alloys and then decreases slowly. The easy magnetization direction (EMD) of (Sm0.5Nd0.5)2(Fe0.25Co0.75)17 is along the c-axis and a strong enhancement of the crystalline anisotropy energy constant K is produced by the addition of some Co atoms. The anisotropy energy constant reaches the maximum when x = 0.75 and then decreases slowly with the Co content further increasing. The (Sm0.5Nd0.5)2(Fe0.25Co0.75)17compound is an optical candidate for the new permanent magnet, which possesses a high magnetization, a high Curie temperature,     

IN SITU TEM OBSERVATION OF AMORPHOUS Nd_xFe_(1-x)THIN FILMS AND THEIR CRYSTALLIZATION

The room temperature stability and crystallization of amorphous Nd_xFe_(1-x)thin filmswith x=0.06—0.90,prepared by flash evaporation at 77 K,were investigated by X-raydiffraction and TEM observation.The amorphous Nd_xFe_(1-x)films are stable at roomtemperature when 0.19相似文献   

Abnormal saturation magnetization dependency on W content for Co-W thin films

A series of hexagonal close-packed (HCP) Co-W thin films were deposited by sputtering on surface oxidized silicon substrates at 300℃. A linear dependency of saturation magnetization (M_s) on W content was found up to about 9~at.~pct W, and then it underwent an increased M_s vs. W content curve as compared to the initial linear dependency. The thermal magnetization technique was used to confirm that the increased M_s behaviour is correlated to the phase separation of the Co-W thin films. The phase separation behaviour was also found to be dependent on W content and the reason was discussed in detail. Finally an interesting composition range was suggested to be about 13at.pct-17 at. pct W for the Co-W thin films, in which they exhibit much higher magnetic anisotropy energy than Co-Cr thin films and improved phase separation.     

Structural and magnetic properties of Sm2Fe17-xNbx （x = 0-4） alloys prepared by HDDR processes and their nitrides

Sm2Fe17-xNbx （x = 0-4） powder was synthesized by HDDR treatment and nitrogenation. The effects of partial Nb substitution for Fe on the structural and magnetic properties of Sm2Fe17-xNbx alloys and their nitlides were investigated. It was seen that Sm2（Fe,Nb）17 phase exists in both annealed and HDDR-treated Sm2Fe17-xNbx alloys. However, its content is decreased with the increase in Nb substitution. In annealed alloys, Sm2（Fe,Nb）17 phase becomes unstable and will dissociate into SmFe2 and Fe-rich phases when x 〉 1.5. With HDDR-treatment, the Nb concentration in recombined Sm2（Fe,Nb）17 phase is decreased, and the content of Fe-rich phases is increased. Sm2Fe17-xNbx powder exhibits dendritic cracks and fine particles with a size of less than 300 nm. In nitrogenated alloys, N atoms mainly enter 2：17-type phase to form Sm2（Fe,Nb）17Ny. Partial Nb atoms in Sm2（Fe,Nb）17Ny phase will be released or excluded by nitrogen atoms. Fe-rich phases increase, and are followed by the amorphous Sm2（Fe,Nb）17Ny phase. Nb substitution for Fe with x = 0.5 and 1.0 in Sm2Fe17-xNbxNy powders increases the coercivity and remanence. But when x is greater than 2.0, Nb substitution will deteriorate the magnetic properties.     

Optical and structural properties of highly porous shell structured Fe doped TiO2 thin films

TiO2thin films with 0.2 wt%, 0.4 wt%, 0.6wt%, and 0.8 wt% Fe were prepared on glass and silicon substrates using sol–gel spin coating technique. The optical cut-off points are increasingly red-shifted and the absorption edge is shifted over the higher wavelength region with Fe content increasing. As Fe content increases, the optical band gap decreases from 3.03 to 2.48 eV whereas the tail width increases from 0.26 to 1.43 eV. The X-ray diffraction（XRD） patterns for doped films at 0.2 wt% and0.8 wt% Fe reveal no characteristic peaks, indicating that the film is amorphous whereas undoped TiO2exhibits（101） orientation with anatase phase. Thin films of higher Fe content exhibit a homogeneous, uniform, and nanostructured highly porous shell morphology.     

Structure and intrinsic magnetic properties of Sm_(1-x)Pr_xCo_5(x=0–0.6) compounds

In this work, the effects of Pr content on the structure and intrinsic magnetic properties of Sm_(1-x)Pr_xCo_5(x = 0–0.6) compounds prepared by induction melting were systematically investigated by scanning electron microscopy(SEM), X-ray diffraction(XRD), and magnetic measurements. Microstructural observation and chemical composition analysis show that Sm_(1-x)Pr_xCo_5 compounds are composed of(Sm, Pr)Co(1:5) phase and(Sm, Pr)-rich grain boundary phase. XRD results show that all the Sm_(1-x)Pr_xCo_5 compounds have a(Sm, Pr)_1Co_5 main phase with the hexagonal CaCu_5-type crystal structure and the(Sm, Pr)_2Co_7 impurity phase. In addition, the detailed research shows that the lattice constants(a, c) and unit volume(V) are all enlarged with the increases in Pr content. According to the magnetic measurements, as the Pr content increases to larger than 0.4, both the Curie temperature(T_C) and the anisotropy field(H_A) of all the Prdoped compounds decrease rapidly. Meanwhile, the magnetization of Sm_(1-x)Pr_xCo_5 compounds at applied field of 14 T(M_(14 T)) are observably improved with Pr doping content of x0.3. Among them, Sm_(0.6)Pr_(0.4)Co_5 compound exhibits slightly lower H_Aand T_C, but much higher M_(14 T) than those of the binary SmCo_5, indicating that doping of proper Pr content into SmCo_5 compound can optimize the intrinsic magnetic properties. As a result, the optimal intrinsic magnetic properties of H_A= 29.11 T,T_C= 989 K, and M_(14 T)= 102.31 mA·m~2·g-1are obtained in Sm_(0.6)Pr_(0.4)Co_5 compound.     

Influence of Annealing Temperature on the Microstructure and Electrical Properties of Indium Tin Oxide Thin Films

Indium tin oxide(ITO) thin films were prepared on alumina ceramic substrates by radio frequency magnetron sputtering.The samples were subsequently annealed in air at temperatures ranging from 500 to 1,100 °C for 1 h.The influences of the annealing temperature on the microstructure and electrical properties of the ITO thin films were investigated,and the results indicate that the as-deposited ITO thin films are amorphous in nature.All samples were crystallized by annealing at 500 °C.As the annealing temperature increases,the predominant orientation shifts from(222)to(400).The carrier concentration decreases initially and then increases when the annealing temperature rises beyond1,000 °C.The resistivity of the ITO thin films increases smoothly as the annealing temperature increases to just below900 °C.Beyond 900 °C,however,the resistivity of the films increases sharply.The annealing temperature has a significant effect on the stability of the ITO/Pt thin film thermocouples(TFTCs).TFTCs annealed at 1,000 °C show improved hightemperature stability and Seebeck coefficients of up to 77.73 μV/°C.     

Microstructure and magnetostrictive properties of Tb doped Fe–Ga bulk alloys prepared by melt quenching

The microstructure and magnetostrictive properties were investigated in the Tb doped Fe83Ga17-xTbx(x = 0.05, 0.10, 0.20, 0.30, 0.40, 0.50) bulk rods prepared by melt rapidly quenching. The partial solid solubility of Tb in the Fe–Ga matrix was preliminary detected by the lattice parameters and SEM observation. The matrix keeps A2 structure and the second phase appears surround the grain boundary as x C 0.1. h100 i preferred orientation is also observed for x = 0.1 sample along the axis of the quenched rod. The saturation magnetostriction first increases and maximum value reaches at x = 0.1, and then decreases with Tb addition increasing. The initial increase of the magnetostriction should be associated with the partial solution of Tb in the matrix, the maximum value at x = 0.1 should be attributed to the h100 i preferred orientation, and the decrease of the magnetostriction is correlated with the appearance of the second phase along the grain boundary.     

PREPARATION OF NANO-CRYSTALLINE Fe-Cu THIN FILMS AND THEIR MAGNETIC PROPERTIES

Fe-Cu thin films of 0.2μm in thickness with different Cu contents were prepared by using r.f. magnetron sputtering onto glass substrate. The effect of sputtering param-eters, including Ar gas pressure and input rf power, on the structure and magnetic properties was investigated. It was found that when the power is lower than 70 W, the structure of the films remained single bcc-Fe phase with Cu solubility of up to 50at.%. TEM observations for the bcc-Fe phase showed that the grain size was in the nanometer range of less than 20nm. The coercivity of Fe-Cu films was largely affected by not only Ar gas pressure but also rf power, and reached about 2.5Oe in the pressure of 0.67-6.67Pa and in the power of less than WOW. In addition, saturation magnetization, with Cu content less than 60at. %, was about proportional to the con-tent of bcc-Fe. When Cu content was at 60at.%, however, saturation magnetization was much smaller than its calculation value.     

Structure and magnetic properties of Pr0. 1CexTb0.9-xFe1.9 alloys

1　INTRODUCTIONTerfenol D ( Tb0.27 Dy0.73 Fe2 ) exhibits largemagentostriction and minimized magnetic anisotro py at room temperature[1], so it is widely used inactuators and transducers. But the main raw mate rials of Terfenol D are expensive Tb and Dy. Ac cording to the single ion model[2], CeFe2 and PrFe2compounds have larger magnetostriction thanTbFe2 and DyFe2 at 0 K. In addition, Ce and Prare much cheaper than Tb and Dy. So Ce basedand Pr based compo…     

Pr0.3TbxDy0.7-xFe1.9Ti0.1合金结构和磁致伸缩

采用电弧熔炼方法制备了Pr0.3TbxDy0.7-xFe1.9Ti0.1(x=0.18～0.21)合金,对样品进行不同条件退火处理,并测量了其磁性能。结果表明:退火前样品都有杂相,并且第二相很大程度上影响样品磁致伸缩;700℃,6d退火处理没有有效消除杂相,样品磁致伸缩没有明显得到改善;而900℃,3d退火处理有效地消除了样品的杂相,尤其是x=0.21的样品,几乎呈现完美的单一的MgCu2型Laves相,磁化强度和磁致伸缩系数均有所增加,当磁场为900kA/m时该样品磁致伸缩系数达到了1.12×10-3。     

THE SYNTHESIS AND MAGNETOSTRICTION OF P rx Ce 1 x Fe 2 COMPOUNDS

１．ＩｎｔｒｏｄｕｃｔｉｏｎＡｌａｒｇｅｍａｇｎｅｔｏｓｔｒｉｃｔｉｏｎｍｉｇｈｔｂｅｅｘｐｅｃｔｅｄｉｎＰｒＦｅ２ｂａｓｅｄｏｎｓｉｎｇｌｅｉｏｎｍｏｄｅｌｐｒｅｄｉｃｔｉｏｎ〔１〕ａｎｄｉｔｉｓａｐｏｔｅｎｔｉａｌｃａｎｄｉｄａｔｅｆｏｒｇｉａｎｔｍａｇｎｅｔｏｓｔｒｉｃｔｉｖｅｍａｔｅｒｉａｌｓ．Ｈｏｗｅｖｅｒ,ｔｈｅｐｒｅｖｉｏｕｓｒｅｓｅａｒｃｈｅｓｉｎｄｉｃａｔｅｄｔｈａｔｓｏｍｅｒａｒｅｅａｒｔｈｉｒｏｎＬａｖｅｓｐｈａｓｅｃｏｍｐｏｕｎｄｓＲＦｅ２（Ｒ＝Ｌａ,Ｐｒ,Ｎｄ,Ｅ…     

MAGNETOSTRICTIVE BEHAVIOUR OF R（Fe_（1－x）Al_x）_y ALLOYS（R＝Dy_（0．65）Tb_（0．25）Pr_（0．1））

ＭＡＧＮＥＴＯＳＴＲＩＣＴＩＶＥＢＥＨＡＶＩＯＵＲＯＦＲ（Ｆｅ_（１－ｘ）Ａｌ_ｘ）_ｙＡＬＬＯＹＳ（Ｒ＝Ｄｙ_（０．６５）Ｔｂ_（０．２５）Ｐｒ_（０．１））￥ＷＡＮＧＢｏｗｅｎ;ＷＵＣｈａｎｇｈｅｎｇ;ＺＨＵＡＮＧＹｕｚｈｉ;ＪＩＮＸｉｍｅｉ;ＬＩＪｉ...     

Effects of carbon on Pr0.15Tb0.30Dy0.55Fe1.85 compound

The structure, Curie temperature and magnetostriction of Pr0.15Tb0.30Dy0.55Fe1.85Cx (x=0-0.1) compounds were investigated by X-ray diffraction, a vibrating sample magnetometer and a standard strain technique.All the samples show entirely MgCu2-type Laves phase structure.The lattice parameter and Curie temperature increase with C content increasing.The magnetostriction at high magnetic field shows maximum value at x=0.05.     

Effects of Zr on crystallization kinetics of Pr—Fe—B amorphous alloys

The effects of Zr on crystallization kinetics of Pr-Fe-B amorphous alloys have been investigated by DTA and XRD methods.It was found that for Pr8Fe86-xZrxB6(x=0,1,2)amorphous alloys,the final crystallized mixture is α-Fe and Pr2Fe14B,and the metastable Pr2Fe23B3 phase occurs during crystallization of Pr8Fe86B6 amorphous alloy,not during crystallization of Pr8Fe86-xZrxB6(x=1,2)amorphous alloys,By analyzing the activation energy of crystallization,the formation of an α-Fe/Pr2Fe14B composite microstructure with a coarse grain size in annealed Pr8Fe86B6 alloy,is attributed to a difficult nucleation and an easy growth for both the α-Fe and Pr2Fe14B in the alloy.The addition of Zr can be used to change the crystallization behavior of the α-Fe phase in Pr-Fe-B amorphous alloy,which is helpful to reduce the grain size for the α-Fe phase.     

Tb0.3Dy0.7Fe1.95-xNbx (x=0, 0.03, 0.06, 0.09) 合金的组织与磁致伸缩性能

采用高真空电弧炉制备了Tb0.3Dy0.7Fe1.95-xNbx(x=0,0.03,0.06,0.09)合金,研究了该系列合金的晶体结构、微观组织及磁致伸缩性能。结果表明:添加Nb元素后的Tb0.3Dy0.7Fe1.95-xNbx(x=0.03,0.06,0.09)合金基体相结构仍保持为MgCu2(C15型)立方Laves相,添加Nb后Tb0.3Dy0.7Fe1.95-xNbx合金基体相晶格常数几乎不变。Nb在基体相RFe2中和富Re相中都不溶,但在x=0.03时的RFe3相中微溶而形成Re(Nb,Fe)3相。初生相NbFe2(C14型)相的形成使凝固液体富稀土从而抑制了RFe3有害相形成。六方结构的NbFe2在与自身结构不同的RFe2(C15型)中不溶而单独成为一相存在于RFe2基体上。Nb的添加量x对磁致伸缩的影响很大,微量(x=0.03)Nb的添加有效抑制了RFe3有害相的生成而使得磁致伸缩性能提高最大,但当Nb含量继续增大时,由于顺磁相NbFe2和富Re相的析出影响了基体磁-弹性交互作用而使磁效伸缩性能下降。但相对于Tb0.3Dy0.7Fe1.95母合金都有少量提高。     

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 研究了非晶丝材磁致伸缩系数的小角转动测量方法，采用小角转动法(SAMR)测量了Co69.9Si12.5B9Fe5Cr3.5Mo0.1非晶合金丝感应电压的二次谐波信号随直流偏磁场、应力及驱动电流的变化关系，通过对测量条件的优化，测量了非晶丝感生各向异性场随应力的变化关系。得到Co69.9Si12.5B9Fe5Cr3.5Mo0.1非晶丝的磁致伸缩系数λs为1′10-7。