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1.
系统研究了室温下Tb0.3Dy0.7-xPrx(Fe0.9Al0.1)1.95 (x=0,0.1,0.2,0.25,0.3,0.35)合金中稀土元素Pr替代Dy对晶体结构、磁致伸缩、各向异性和自旋重取向的影响. 结果发现,x≤0.1时,Tb0.3Dy0.7-xPrx(Fe0.9Al0.1)1.95完全保持MgCl2立方Laves相结构,0.1<x≤0.3,有杂相出现并且随Pr替代量逐渐增多;晶格常数a随Pr含量x的增加缓慢增大. 磁致伸缩测量发现,随着替代量x的增多磁致伸缩减小;x>0.2时超磁致伸缩效应消失. 然而,x=0.1时合金的磁致伸缩略大于没有替代的,而且磁致伸缩随磁场更易趋于饱和,说明Pr替代有助于降低磁晶各向异性. 内禀磁致伸缩λ111随Pr替代量x的增加接近线性增加. 由相对磁化率随温度的变化关系可以看出,自旋重取向温度随Pr替代量的增多呈先增后降趋势,在x=0.1处出现极大值. 穆斯堡尔效应表明,随Pr含量的增加Tb0.3Dy0.7-xPrx(Fe0.9Al0.1)1.95合金中易磁化轴可能在{110}面上绕主对称轴作微小转动,发生自旋重取向. 与Al元素替代效应相比,Pr替代Dy对自旋重取向的影响相对较小.  相似文献   

2.
The effect of Pr substitution for Dy on the magnetic and magnetostrictive properties, anisotropy, spin reorientation and M?ssbauer effect of a series of Tb0.3Dy0.7−x Pr x (Fe0.9Al0.1)1.95 (x=0, 0.1, 0.20, 0.25, 0.30, 0.35) alloys at room temperature have been investigated. It was found that a small amount of Pr substitution is beneficial to a decrease in the magnetocrystalline anisotropy for the Tb0.3Dy0.7−x Pr x (Fe0.9Al0.1)1.95 alloys. The magnetostriction decreases drastically with increasing x and the magnetostrictive effect disappears for x>0.2. However, the magnetostriction exhibits a slightly bigger value at x=0.1 than the free alloys and is saturated more easily with the magnetic field H. The saturation magnetization and Curie temperature decrease monotonously, but the spontaneous magnetostriction increases linearly with increasing x, whereas the spin reorientation temperature increases first, then decreases rapidly and reaches the maximum at x=0.1. The analysis of M?ssbauer spectra indicated that the easy magnetization direction in the {110} plane deviates slightly from the main axis of symmetry with the Pr concentration x, namely spin reorientation. Compared with Al substitution for Fe, the effect of Pr substitution for Dy on spin reorientation is relatively small. The hyperfine field increases with Pr concentration increasing, and the isomer shifts and the quadrupole splitting (QS) show weak concentration dependence. Supported by the National Natural Science Foundation of China (Grant No. 10574059), the Natural Science Foundation of Gansu Province (Grant No. 0710RJZA074), the Second Scientific Research Project of Bureau of Gansu Education and ‘Qing Lan’ Talent Engineering Funds of Lanzhou Jiaotong University  相似文献   

3.
The effect of Al substitution for Fe on crystal structure, magnetostriction and spontaneous magnetostriction, anisotropy and spin reorientation of a series of polycrystalline Tb0.3Dy0.7(Fe1−x Alx)1.95 alloys (x = 0, 0.05, 0.1, 0.15, 0.20, 0.25, 0.30, 0.35) at room temperature and 77 K was investigated systematically. It was found that the primary phase of Tb0.3Dy0.7(Fe1−x Alx)1.95 is the MgCu2-type cubic Laves phase structure when x < 0.4 and the lattice constant a of Tb0.3Dy0.7(Fe1−x Alx)1.95 increases approximately and monotonically with the increase of x. The substitution of Al leads to the fact that the magnetostriction λ inceases slightly in a low magnetic field (H ⩽ 40 kA/m), but decreases sharply and is easily close to saturation in a high applied field as x increases, showing that a small amount of Al substitution is beneficial to a decrease in the magnetocrystalline anisotropy. It was also found that the spontaneous magnetostriction λ 111 decreases greatly with x increasing. The analysis of the M?ssbauer spectra indicated that the easy magnetization direction in the {110} plane deviates slightly from the main axis of symmetry with the changes of composition and temperature, namely spin reorientation. A small amount of non-magnetic phase exists for x = 0.15 in Tb0.3Dy0.7(Fe1−x Alx)1.95 alloys and the alloys become paramagnetic for x > 0.15 at room temperature, but at 77 K the alloys still remain magnetic phase even for x = 0.2. At room temperature and 77 K, the hyperfine field decreases and the isomer shifts increase with Al concentration increasing.  相似文献   

4.
The effect of IIIA metal and transition metalT substitution for Fe on crystal structure, magnetostriction and spontaneous magnetostriction, anisotropy and spin reorientation of a series of polycrystalline Tb0.3 Dy0.7 (Fe0.9 T 0.1)1.95 (T=Mn, Fe, Co, B, Al, Ga) alloys at room temperature were investigated systematically. It was found that the primary phase of the Tb0.3 Dy0.7 (Fe0.9 T 0.1)1.95 alloys is the MgCu2-type cubic Laves phase structure for different substitution. The magnetostriction λ{ins} decrases greatly for the substitution of IIIA metal, B, Al and Ga, but is saturated more easily for Al and Ga substitution, showing that the Al and Ga substitution is beneficial to a decrease in the magnetocrystalline anisotropy of Tb0.3 Dy0.7 (Fe0.9 T 0.1)1.95 alloys. However, the substitution of transition metal Mn and Co decreases slightly the magnetostriction λ{ins}. It was also found that the effect of different substitutions on the spontaneous magnetostriction λ{in111} is distinct. The analysis of the M?ssbauer spectra indicates that the easy magnetization direction in the {110} plane deviates slightly from the main axis of symmetry for Al and Ga substitution, namely spin reorientation, but it does not change evidently for B, Mn and Co substitution.  相似文献   

5.
郑小平  张佩峰  李发伸  郝远 《物理学报》2009,58(8):5768-5772
系统研究了室温下Tb0.3Dy0.6Pr0.1(Fe1-xAlx1.95x=0.05,0.1,0.15,0.2,0.25,0.3)合金中元素Al替代Fe对结构、磁性、磁致伸缩性能和自旋重取向的影响.测量结果发现,x<0.2时Tb0.3Dy0.6Pr0.1(Fe1-xAlx1.95合金基本上是纯的单相,x=0.2时出现其他杂相,杂相随Al替代量的增加不断增多.随Al替代量x的增加,点阵常数a接近于线性增大,Curie温度TC逐渐下降,而矫顽力Hc急剧下降.振动样品磁强计(VSM)测量发现,磁化强度M随Al替代量x的变化较为复杂.VSM计和磁致伸缩效应测量共同表明,少量Al的替代有利于降低磁晶各向异性,而且随着Al替代量x的增多磁致伸缩系数快速减小,x>0.15时巨磁致伸缩效应消失.穆斯堡尔效应研究发现,随Al含量的增加Tb0.3Dy0.6Pr0.1(Fe1-xAlx1.95合金中易磁化轴可能在{110}面逐渐偏离了立方晶体的主对称轴,发生自旋重取向,从而引起合金宏观磁性、磁致伸缩性能的变化. 关键词: 磁致伸缩 立方Laves相 自旋重取向 穆斯堡尔谱  相似文献   

6.
The structure and magnetostriction of the (Tb1−xDyx)0.2Pr0.8(Fe0.4Co0.6)1.88C0.05 intermetallic compounds (0≤x≤1) were studied by X-ray diffraction and magnetic measurements. The formation of an approximate single Laves phase with a MgCu2-type cubic structure was observed in this series of compounds. It was found that the Curie temperature and the saturation magnetization of the compounds would decrease with increase in the Dy content up to x=1. The magnetostriction λa (λa=λ-λ) gently rises when x≤0.6, and follows with a precipitous fall when x exceeds 0.6, with the highest value of λa being reached in the compounds with x=0.6. The magnetostriction of all the samples was observed to approach their own saturation in the magnetic fields higher than 4 kOe. This indicates that the addition of a small amount of Dy could effectively improve the low-field magnetostriction of the Tb0.2Pr0.8(Fe0.4Co0.6)1.88C0.05 compounds, which could become a kind of promising magnetostrictive material.  相似文献   

7.
系统研究了室温下Tb0.3Dy0.7(Fe0.9T0.1)1.95(过渡金属元素T=Mn,Fe,Co,B,Al,Ga)合金中ⅢA族金属和过渡金属元素T替代Fe对结构、自旋重取向和穆斯堡尔谱的影响.结果发现,不同金属T替代Fe,Tb0.3Dy0.7(Fe0.9T0.1)1.95,合金具有相同的MgCu2型立方Laves相结构;Al,Ga替代使Tb0.3Dy0.7(Fe0.9T0.1)1.95合金的易磁化方向在{110}面逐渐偏离了立方晶体的主对称轴,即自旋重取向,B,Mn,Co替代未使易磁化轴发生明显转动;Al,Ga元素替代使超精细场Hhf略有下降,B,Mn替代对超精细场Hhf的影响不大,而Co元素替代使超精细场Hhf有较大增加;所有元素替代使同质异能移IS有所增加;B,Al,Ga和Mn替代使四极劈裂Qs增加,而Co替代使四极劈裂Qs下降. 关键词: 立方Laves相 自旋重取向 穆斯堡尔谱  相似文献   

8.
The effect of IIIA metal and transition metalT substitution for Fe on crystal structure, magnetostriction and spontaneous magnetostriction, anisotropy and spin reorientation of a series of polycrystalline Tb0.3 Dy0.7 (Fe0.9 T 0.1)1.95 (T=Mn, Fe, Co, B, Al, Ga) alloys at room temperature were investigated systematically. It was found that the primary phase of the Tb0.3 Dy0.7 (Fe0.9 T 0.1)1.95 alloys is the MgCu2-type cubic Laves phase structure for different substitution. The magnetostrictionλ s decrases greatly for the substitution of IIIA metal, B, Al and Ga, but is saturated more easily for Al and Ga substitution, showing that the Al and Ga substitution is beneficial to a decrease in the magnetocrystalline anisotropy of Tb0.3 Dy0.7 (Fe0.9 T 0.1)1.95 alloys. However, the substitution of transition metal Mn and Co decreases slightly the magnetostrictionλ s . It was also found that the effect of different substitutions on the spontaneous magnetostrictionλ 111 is distinct. The analysis of the Mössbauer spectra indicates that the easy magnetization direction in the {110} plane deviates slightly from the main axis of symmetry for Al and Ga substitution, namely spin reorientation, but it does not change evidently for B, Mn and Co substitution.  相似文献   

9.
The axial and transversal linear magnetostrictions (λ and λ) in [1 1 0] oriented polycrystalline Tb0.3Dy0.7Fe1.95 alloys were measured simultaneously under uniaxial magnetomechanical loading to get the forced volume magnetostriction (ω=λ+2λ). Despite the almost zero ω observed in Terfenol-D single crystals, it reaches up to 1000×10−6 in polycrystalline Tb0.3Dy0.7Fe1.95 alloys near the saturation magnetic field under a stress above 50 MPa.  相似文献   

10.
The C15 Laves phases with composition Nd1−xPrx(Fe0.35Co0.55B0.1)2 (0?x?1) have been synthesized by arc melting and subsequent annealing. The Curie temperature Tc and the saturation magnetizations Ms at 5 and 295 K decrease with increasing Pr content. The linear anisotropic magnetostriction λa=λλ at room temperature for Nd1−xPrx(Fe0.35Co0.55B0.1)2 alloys with 0?x?0.4 initially reaches a negative minimum, then increases and changes its sign with increasing magnetic field H, and the λa for the alloys with x?0.6 is positive and increases as magnetic field H increases.  相似文献   

11.
The Tb0.29(Dy1−xPrx)0.71Fe1.97 (x=0, 0.1, 0.2 and 0.3) alloys were prepared by directional solidification method. The orientation, magnetostriction λ, Curie temperature Tc and microstructure of alloys were characterized by XRD, standard resistant strain gauge technique, VSM and SEM-EDS. The results reveal that the alloys have a preferred orientation of 〈1 1 0〉 and 〈1 1 3〉 direction when x>0. With the increase in Pr content, the Tc of alloys decreases gradually and the non-cubic phase appears, resulting in the decline of λ dramatically, from 1935.2×10−6 for x=0 to 695.9×10−6 for x=0.3 at a compressive stress of 6 MPa and a magnetic field of H=240 kA m−1.  相似文献   

12.
Measurement of X-ray diffraction, magnetization and magnetostriction was made on the Pr(Fe1-xCox)2 (x=0.4, 0.5 and 0.6) and Pr1-yTby(Fe0.4Co0.6)2 (y=0, 0.1, 0.2 and 0.3) alloy series. It was found that a cubic phase with the MgCu2 structure can be obtained in the Pr(Fe1-xCox)2 series only at x=0.6. The Pr1-yTby(Fe0.4Co0.6)2 system has the cubic MgCu2 structure over the studied range for y. The lattice constant and magnetization decrease and the Curie temperature increases with increasing y. At 7 K, Pr1-yTby(Fe0.4Co0.6)2 samples are found to have huge intrinsic coercivities, which are associated with narrow domain walls. It is also found from X-ray measurement that in Pr1-yTby(Fe0.4Co0.6)2 the spontaneous magnetostriction 111 increases due to Tb substitution, while the saturation magnetostriction s is much lower than 111. This can be attributed to the large value of 100 with an opposite sign to 111, which may be caused by the filling of the d band due to Co substitution. PACS 75.80.-g; 61.10.-i; 75.60.-d  相似文献   

13.
The structure, Curie temperature and magnetostriction of Pr0.15Tb0.3Dy0.55Fe1.85−xBx   (x=0–0.3x=00.3) alloys have been investigated using X-ray diffraction, AC susceptibility and standard strain gauge techniques. It was found that all the samples possess entirely MgCu2-type cubic Laves structure. With increasing B concentration, the lattice parameter decreases, while the Curie temperature remains unchanged. The magnetostriction of Pr0.15Tb0.3Dy0.55Fe1.85−xBx alloys at room temperature increases with increasing B concentration firstly, and then decreases slightly.  相似文献   

14.
Structure, Curie temperature and magnetostriction of RFex (1.6 ? x ? 2.0) and R(Fe1−yTiy)1.8 (y ? 0.2) alloys (RDy0.65Tb0.25Pr0.1) have been investigated using optical microscopy, X-ray diffraction, AC initial susceptibility and standard strain gauge techniques. The homogenized RFex alloys are found to be essentially single phase in the range of 1.8 ? x ? 1.85. The second phase is a rare-earth-rich phase when x ? 1.8, and (Dy, Tb, Pr)Fe3 phase when x ? 1.85. X-ray diffraction indicates that the R(Fe1−yTiy)1.8 alloys contain a small amount of Fe2Ti phase when y ? 0.05, which increases with the increment of Ti content. The Curie temperature of R(Fe1yTiy)1.8 alloys slightly enhances with increasing Ti concentration when y ? 0.05, then remains almost unchanged in the range of 0.05 ? y ? 0.20. The magnetostriction of RFex alloys is improved when x ? 1.80 and reduced by increasing Fe content when x ? 1.85. The magnetostriction of R(Fe1−yTiy)1.8 alloys is lowered by increasing Ti content.  相似文献   

15.
The structure and magnetic properties of the melt-spun ribbons of Tb0.27Dy0.73Fex alloy are investigated as a function of various wheel speeds during melt-quenching using a single-roll technique. It is found that Tb0.27Dy0.73Fex alloy is difficult to be fabricated as amorphous state by using the melt-quenching method. X-ray diffractions show that all these ribbons for x=1.7−2.0 are the MgCu2-type phase at the wheel speed of 45 m s−1. For Tb0.27Dy0.73Fex alloy, the high wheel speed is beneficial to eliminate the RFe3 phase and form the perfect MgCu2-type phase. Compared with the bulk of Tb0.27Dy0.73Fe1.95, these ribbons exhibit higher intrinsic coercivity value and their saturation magnetizations increase as well. The magnetostriction of Tb0.27Dy0.73Fe1.95 composite with 4% epoxy resin is 640×10−6 at 900 kA m−1.  相似文献   

16.
The structure and magnetostriction of Tb0.2Pr0.8(Fe0.4Co0.6)1.93−xCx intermetallic compounds were studied by X-ray diffraction and magnetic measurements. Almost a single cubic Laves phase forms in the alloys for x ≤0.20, and a small amount of C can inhibit the formation of the 1:3 phase. The lattice parameter increases when 0≤x≤0.15, while the Tc and the spontaneous magnetization decreases with increasing x. The lattice parameter decreases slowly when 0.15≤x≤0.30, while the Tc decreases evidently with increasing x. The magnetostriction λa (=λ-λ) is improved at low magnetic fields at room temperature for the compounds with 0.05≤x≤0.10, indicating that these C-containing compounds are promising magnetostrictive materials.  相似文献   

17.
Zheng  Xiaoping  Li  Fashen  Cheng  Zhaohua  Shen  Baogen 《Hyperfine Interactions》2002,142(3-4):503-511
A structural, magnetic and Mössbauer study of a series of Tb0.3Dy0.7(Fe1–x Al x )1.95 alloys (x=0, 0.05, 0.1, 0.15, 0.20, 0.25, 0.30, 0.35) at room temperature is presented. It was found that the primary phase of the Tb0.3Dy0.7(Fe1–x Al x )1.95 alloys is the MgCu2-type cubic Laves phase structure when x<0.3 and a small amount of a second phase, RFe3 (R: rare-earth element), is present when 0.3x0.35. The lattice constant of the Tb0.3Dy0.7(Fe1–x Al x )1.95 alloys increases approximately monotonically with increasing x. The substitution of Al increases slightly the magnetostriction in a low magnetic field (H500 Oe). However, the magnetostriction decreases sharply, but is saturated more easily with increasing x in a higher applied field. The analysis of the Mössbauer spectra allows the determination of the easy axes of magnetization in these alloys. Moreover, the dependence of the hyperfine-field, isomer shift and quadrupole splitting on the Al concentration, x, for the Tb0.3Dy0.7(Fe1–x Al x )1.95 alloys are reported and discussed.  相似文献   

18.
The crystal structure, magnetic and magnetostrictive properties of high-pressure synthesized PrxNd1-xFe1.9 (0≤x≤1.0) alloys were studied. The alloys exhibit single cubic Laves phase with MgCu2-type structure. The initial magnetization curve reveals that Pr0.2Nd0.8Fe1.9 has a minimum magnetocrystalline anisotropy at 5 K. The magnetostriction curve at 5 K shows that Pr0.2Nd0.8Fe1.9 has a very good low-field magnetostrictive property, and the magnetostriction of the PrxNd1-xFe1.9 alloy in high magnetic field is attributable mainly to Pr. The temperature dependence of the magnetostriction (λ||) at the field of 5 kOe shows that the substitution of Nd reduces the K1 remarkably, and the values of λ|| of Pr0.2Nd0.8Fe1.9 and Pr0.8Nd0.2Fe1.9 alloys are nearly five times larger than that of PrFe1.9 alloy below 50 K; the λ|| of Pr0.8Nd0.2Fe1.9 reaches up to 1082 ppm at 100 K, which makes it a potential candidate for application in this temperature range.  相似文献   

19.
Structure, Curie temperature and magnetostriction of RFex (1.6 x 2.0) and R(Fe1−yTiy)1.8 (y 0.2) alloys (R=Dy0.65Tb0.25Pr0.1) have been investigated using optical microscopy, X-ray diffraction, AC initial susceptibility and standard strain gauge techniques. The homogenized RFex alloys are found to be essentially single phase in the range of 1.8 x 1.85. The second phase is a rare-earth-rich phase when x 1.8, and (Dy, Tb, Pr)Fe3 phase when x 1.85. X-ray diffraction indicates that the R(Fe1−yTiy)1.8 alloys contain a small amount of Fe2Ti phase when y 0.05, which increases with the increment of Ti content. The Curie temperature of R(Fe1yTiy)1.8 alloys slightly enhances with increasing Ti concentration when y 0.05, then remains almost unchanged in the range of 0.05 y 0.20. The magnetostriction of RFex alloys is improved when x 1.80 and reduced by increasing Fe content when x 1.85. The magnetostriction of R(Fe1−yTiy)1.8 alloys is lowered by increasing Ti content.  相似文献   

20.
The effects of Al substitution for Fe on the structure, magnetics, magnetostriction, anisotropy and spin reorientation of a series of Tb0.3Dy0.6Pr0.1(Fe1-xAlx)1.95 alloys (x=0.05, 0.1, 0.15, 0.2, 0.25, 0.3) at room temperature have been investigated. The alloys of Tb0.3Dy0.6Pr0.1(Fe1-xAlx)1.95 substantially retain MgCu2-type C-15 cubic Laves phase structure when x0.2. The mixed phases appear with x = 0.2, and cubic Laves phase decreases with increasing x. The magnetostriction of the Tb0.3Dy0.6Pr0.1(Fe1-xAlx)1.95 alloys decreases drastically with increasing x and the giant magnetostrictive effect disappears for x 0.15. Fortunately, a small amount of Al substitution is beneficial to a decrease in the magnetocrystalline anisotropy. The spin reorientation temperature decreases with increasing x. The analysis of the Mssbauer spectra indicates that the easy magnetization direction in the {110} plane deviates slightly from the main axis of symmetry with the increase of Al concentration x, namely, spin reorientation, resulting in the change of macroscopical magnetic properties and magnetostriction. The hyperfine field decreases, but the isomer shifts increases with Al concentration increasing and the quadruple splitting QS shows a weak concentration dependence.  相似文献   

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