The crystal structures, magnetization, and spontaneous magnetostriction of ferromagnetic Laves phase Pr1-xTbxFe1.9 compounds are investigated in a temperature range between 5 K and 300 K. High resolution synchrotron x...The crystal structures, magnetization, and spontaneous magnetostriction of ferromagnetic Laves phase Pr1-xTbxFe1.9 compounds are investigated in a temperature range between 5 K and 300 K. High resolution synchrotron x-ray diffraction(XRD) analysis shows that different proportions of Tb in Pr1-xTbxFe1.9 alloys can result in different easy magnetization directions(EMD) below 70 K, i.e., [100] with x = 0.0, and [111] with x ≥ 0.1. This indicates Tb substitution can lead the EMD to change from [100] to [111] with x rising from 0.0 up to 0.1. The Tb substitution for Pr reduces the saturation magnetization Ms and the magnetostriction to their minimum value when x = 0.6, but it can increase low-field(0 ≤ H ≤9 kOe, the unit 1 Oe = 79.5775 A·m-1) magnetostriction when x = 0.8 and 1.0 at 5 K. This can be attributed to the larger magnetostriction of PrFe1.9 than that of TbFe1.9, as well as the decrease of the resulting anisotropy due to Tb substitution at low temperatures.展开更多
By Mossbauer-effect, the changes of easy direction of magnetization for Sm0.88Dy0.12.Fe2 alloy have been studied in this paper. It was found that as temperature increases, the easy direction of magnetization changes...By Mossbauer-effect, the changes of easy direction of magnetization for Sm0.88Dy0.12.Fe2 alloy have been studied in this paper. It was found that as temperature increases, the easy direction of magnetization changes gradually from [110] to [111] axis in the temperature range of 153 to 213 K. Two easy directions of magnetization [110] and [111] coexist and do not change suddenly from [110] to [111] at the same temperature.展开更多
In order to prepare the bulk samples with high residual magnetization of magnetic compounds, such as (Sm, La)2(Co,Cu,Fe,Zr)17, (Sm,La)1(Co,Cu, Fe)5, Nd2Fe14B, and Pr2Fe14B, directly prepared by solidification, or hot-...In order to prepare the bulk samples with high residual magnetization of magnetic compounds, such as (Sm, La)2(Co,Cu,Fe,Zr)17, (Sm,La)1(Co,Cu, Fe)5, Nd2Fe14B, and Pr2Fe14B, directly prepared by solidification, or hot-deformation , it is the first thing to explore the possibilities of the easy magnetization axis of the whole bulk samples to be arranged in one designed direction. a is defined as the angle between the axis and the direction. In Sm-La-Co-Fe-Cu-Zr system, whetherαis equal to 0°or 90°depends upon not only alloy compositions but also the ratio of the temperature gradient at the solid/liquid interface and the crystal growth rate. To some alloys, a can be changed from 90°to 0°if the ratio is increased to be higher than a critical value, so the c-axis texture orientation can be obtained. In Nd-Fe-B system, the easy magnetization axis of Nd2Fe14B is always perpendicular to the preferential growth direction [ 100], and the easy magnetization axes of Nd2Fe14B grains are randomly distributed in the plane normal to the growth direction even if the growth rate is decreased from 250 to 12μm·-1. But if the magnetization axis of the anisotropic magnet substrate is perpendicular to the heat flux direction of the laser melting solidification layer, c-axis texture of the columnar Nd2Fe14B grains in the layer can be obtained, which is the same as that of the substrate, if the laser scanning rate is not less than 25μm·s-2. Also the c-axis texture [006] can be achieved through hot-deformation of PrxFe93.5-xB5Cu1.5(x = 15 - 19) under the conditions of hot-pressing temperature 973 ~ 1273 K, strain rate 10-3 S-1, and strain 50% ~ 80% .展开更多
The structures, spin reorientations, magnetic, and magnetostrictive properties of the polycrystalline Pr（Fe1-xCox）1.9 （x=0-1.0） cubic laves phase alloys between 5 K and 300 K are investigated. Large low-field magn...The structures, spin reorientations, magnetic, and magnetostrictive properties of the polycrystalline Pr（Fe1-xCox）1.9 （x=0-1.0） cubic laves phase alloys between 5 K and 300 K are investigated. Large low-field magnetostrictions are observed at 5 K in the alloys with x=0.2 and 0.4 due to the low magnetic anisotropies of these two alloys. A large negative magnetostriction of about-1130 ppm is found in PrCo1.9 alloy at 5 K. The magnetizations of the alloys with 0 ≤ x ≤ 0.6 decrease abnormally at the spin reorientation temperature Tsr, and an abnormity is detected in the alloy with x=1.0 at its Curie temperature Tc （45 K）. The substitution of Fe by Co increases the value of Tsr in the alloy with x value increasing from 0.0 to 0.4, and then reduces the value of Tsr with x value further increasing to 0.6.展开更多
The magnetostrictive effects of substituting A1 for Fe in Pr（AlxFe1-x）1.9 （x = 0.0, 0.02, 0.05, 0.10） alloys between 5 K and 300 K were investigated. The substitution decreases the Curie temperature and the value ...The magnetostrictive effects of substituting A1 for Fe in Pr（AlxFe1-x）1.9 （x = 0.0, 0.02, 0.05, 0.10） alloys between 5 K and 300 K were investigated. The substitution decreases the Curie temperature and the value of λ111. Fortunately, the substitution slightly increases the magnetostriction in a low magnetic field, which imbues these materials with potential advantages for applications. Rotation of the easy magnetization direction （EMD） from [ 111 ] to [ 100] in the Pr（A10.02Fe0.98）1.9 alloy as temperature decreases was detected by step scanned XRD reflections.展开更多
The magnetostriction, magnetization, and spin reorientation properties in Pr(Ga_(x)Fe_(1-x))_(1.9) alloys have been investigated by high-precision x-ray diffraction(XRD) step scanning, magnetization, and Mossbauer spe...The magnetostriction, magnetization, and spin reorientation properties in Pr(Ga_(x)Fe_(1-x))_(1.9) alloys have been investigated by high-precision x-ray diffraction(XRD) step scanning, magnetization, and Mossbauer spectra measurements. Ga substitution reduces the magnetostriction(λ_(||)) with magnetic field H ≥ 8 kOe(1 Oe = 1.33322×10^(2) Pa), but it also increases the λ|| value when H ≤ 8 kOe at 5 K. Spin-reorientations(SR) are observed in all the alloys investigated, as determined by the step scanned XRD, Mossbauer spectra, and the abnormal temperature dependence of magnetization. An increase of the spin reorientation temperature(T_(SR)) due to Ga substitution is found in the phase diagram, which is different from the decrease one in many R(T_(x) Fe_(1-x))_(1.9)(T = Co, Al, Mn) alloys. The present work provides a method to control the easy magnetization direction(EMD) or T_(SR) for developing an anisotropic compensation system.展开更多
In this note, relationships among the components, structure distribution and easy magnetization direction, structure of magnetic domain of nano-magnetic material in the major mature lateral radula teeth of chiton A. r...In this note, relationships among the components, structure distribution and easy magnetization direction, structure of magnetic domain of nano-magnetic material in the major mature lateral radula teeth of chiton A. rubrolinestus Lischke are probed by using the high resolution transmission electron microscope (HRTEM), the scanning electron microscope (SEM), the magnetic force microscope (MFM) and the super-conducting quantum interference device (SQUID) magnetometer from the point of view of magnetism to provide a basis for comprehending biologic function of the magnetic radula.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.51901052)the Science Foundation of Guangxi Zhuang Autonomous Region,China(Grant No.2018GXNSFAA281294)
文摘The crystal structures, magnetization, and spontaneous magnetostriction of ferromagnetic Laves phase Pr1-xTbxFe1.9 compounds are investigated in a temperature range between 5 K and 300 K. High resolution synchrotron x-ray diffraction(XRD) analysis shows that different proportions of Tb in Pr1-xTbxFe1.9 alloys can result in different easy magnetization directions(EMD) below 70 K, i.e., [100] with x = 0.0, and [111] with x ≥ 0.1. This indicates Tb substitution can lead the EMD to change from [100] to [111] with x rising from 0.0 up to 0.1. The Tb substitution for Pr reduces the saturation magnetization Ms and the magnetostriction to their minimum value when x = 0.6, but it can increase low-field(0 ≤ H ≤9 kOe, the unit 1 Oe = 79.5775 A·m-1) magnetostriction when x = 0.8 and 1.0 at 5 K. This can be attributed to the larger magnetostriction of PrFe1.9 than that of TbFe1.9, as well as the decrease of the resulting anisotropy due to Tb substitution at low temperatures.
文摘By Mossbauer-effect, the changes of easy direction of magnetization for Sm0.88Dy0.12.Fe2 alloy have been studied in this paper. It was found that as temperature increases, the easy direction of magnetization changes gradually from [110] to [111] axis in the temperature range of 153 to 213 K. Two easy directions of magnetization [110] and [111] coexist and do not change suddenly from [110] to [111] at the same temperature.
基金Project supported by Ministry of Science and Technology (2004CCA04000)Zhejiang Provincial Natural Science Fund of China (M503096)
文摘In order to prepare the bulk samples with high residual magnetization of magnetic compounds, such as (Sm, La)2(Co,Cu,Fe,Zr)17, (Sm,La)1(Co,Cu, Fe)5, Nd2Fe14B, and Pr2Fe14B, directly prepared by solidification, or hot-deformation , it is the first thing to explore the possibilities of the easy magnetization axis of the whole bulk samples to be arranged in one designed direction. a is defined as the angle between the axis and the direction. In Sm-La-Co-Fe-Cu-Zr system, whetherαis equal to 0°or 90°depends upon not only alloy compositions but also the ratio of the temperature gradient at the solid/liquid interface and the crystal growth rate. To some alloys, a can be changed from 90°to 0°if the ratio is increased to be higher than a critical value, so the c-axis texture orientation can be obtained. In Nd-Fe-B system, the easy magnetization axis of Nd2Fe14B is always perpendicular to the preferential growth direction [ 100], and the easy magnetization axes of Nd2Fe14B grains are randomly distributed in the plane normal to the growth direction even if the growth rate is decreased from 250 to 12μm·-1. But if the magnetization axis of the anisotropic magnet substrate is perpendicular to the heat flux direction of the laser melting solidification layer, c-axis texture of the columnar Nd2Fe14B grains in the layer can be obtained, which is the same as that of the substrate, if the laser scanning rate is not less than 25μm·s-2. Also the c-axis texture [006] can be achieved through hot-deformation of PrxFe93.5-xB5Cu1.5(x = 15 - 19) under the conditions of hot-pressing temperature 973 ~ 1273 K, strain rate 10-3 S-1, and strain 50% ~ 80% .
基金Project supported by the National Natural Science Foundation of China(Grant No.U1232210)the Science Foundation of Guangxi Zhuang Autonomous Region,China(Grant No.2015GXNSFBA139020)the Project of the Enhancement of the Basic Ability of Teachers of Guangxi Zhuang Autonomous Region,China(Grant No.KY2016YB068)
文摘The structures, spin reorientations, magnetic, and magnetostrictive properties of the polycrystalline Pr（Fe1-xCox）1.9 （x=0-1.0） cubic laves phase alloys between 5 K and 300 K are investigated. Large low-field magnetostrictions are observed at 5 K in the alloys with x=0.2 and 0.4 due to the low magnetic anisotropies of these two alloys. A large negative magnetostriction of about-1130 ppm is found in PrCo1.9 alloy at 5 K. The magnetizations of the alloys with 0 ≤ x ≤ 0.6 decrease abnormally at the spin reorientation temperature Tsr, and an abnormity is detected in the alloy with x=1.0 at its Curie temperature Tc （45 K）. The substitution of Fe by Co increases the value of Tsr in the alloy with x value increasing from 0.0 to 0.4, and then reduces the value of Tsr with x value further increasing to 0.6.
基金supported by the National Key Project of Fundamental Research of China(Grant Nos.2012CB932304 and 2010CB923404)the National NaturalScience Foundation of China(Grant No.U1232210)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘The magnetostrictive effects of substituting A1 for Fe in Pr（AlxFe1-x）1.9 （x = 0.0, 0.02, 0.05, 0.10） alloys between 5 K and 300 K were investigated. The substitution decreases the Curie temperature and the value of λ111. Fortunately, the substitution slightly increases the magnetostriction in a low magnetic field, which imbues these materials with potential advantages for applications. Rotation of the easy magnetization direction （EMD） from [ 111 ] to [ 100] in the Pr（A10.02Fe0.98）1.9 alloy as temperature decreases was detected by step scanned XRD reflections.
基金supported by the National Natural Science Foundation of China (Grant No. 51901052)the Science Foundation of Guangxi Zhuang Autonomous Region,China (Grant No. 2018GXNSFAA281294)the Training Programme for Thousands of Core Teachers in Guangxi Zhuang Autonomous Region,China。
文摘The magnetostriction, magnetization, and spin reorientation properties in Pr(Ga_(x)Fe_(1-x))_(1.9) alloys have been investigated by high-precision x-ray diffraction(XRD) step scanning, magnetization, and Mossbauer spectra measurements. Ga substitution reduces the magnetostriction(λ_(||)) with magnetic field H ≥ 8 kOe(1 Oe = 1.33322×10^(2) Pa), but it also increases the λ|| value when H ≤ 8 kOe at 5 K. Spin-reorientations(SR) are observed in all the alloys investigated, as determined by the step scanned XRD, Mossbauer spectra, and the abnormal temperature dependence of magnetization. An increase of the spin reorientation temperature(T_(SR)) due to Ga substitution is found in the phase diagram, which is different from the decrease one in many R(T_(x) Fe_(1-x))_(1.9)(T = Co, Al, Mn) alloys. The present work provides a method to control the easy magnetization direction(EMD) or T_(SR) for developing an anisotropic compensation system.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 19874078).
文摘In this note, relationships among the components, structure distribution and easy magnetization direction, structure of magnetic domain of nano-magnetic material in the major mature lateral radula teeth of chiton A. rubrolinestus Lischke are probed by using the high resolution transmission electron microscope (HRTEM), the scanning electron microscope (SEM), the magnetic force microscope (MFM) and the super-conducting quantum interference device (SQUID) magnetometer from the point of view of magnetism to provide a basis for comprehending biologic function of the magnetic radula.
