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Effect of Zn^(2+) Content on the Microstructure and Magnetic Properties of Nanocrystalline Ni_(1-x)Zn_xFe_2O_4 Ferrite by a Spraying-coprecipitation Method 被引量:1
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作者 刘银 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2010年第3期429-431,共3页
Nanocrystalline Ni1-xZnxFe2O4 ferrites with 0≤x≤1 were successfully prepared by a spraying-coprecipitation method.The microstructure was investigated by using XRD and TEM.Magnetic properties were measured with vibra... Nanocrystalline Ni1-xZnxFe2O4 ferrites with 0≤x≤1 were successfully prepared by a spraying-coprecipitation method.The microstructure was investigated by using XRD and TEM.Magnetic properties were measured with vibrating sample magnetometer(VSM) at room temperature.The results show that the grain size of nanocrystalline Ni1-xZnxFe2O4 ferrite calcined at 600 ℃ for 1.5 h is about 30 nm.Lattice parameter and specific saturation magnetization Ms of nanocrystalline Ni1-xZnxFe2O4 ferrite increase with the Zn^2+ ions content at room temperature,and maximum Ms is 66.8 A·m^2·kg^-1 as the Zn^2+ ions content is around 0.5,and coercivity Hc of the nanocrystalline Ni1-xZnxFe2O4 ferrite decreases with Zn^2+ ions content. 展开更多
关键词 nanocrystalline material Ni-Zn ferrite spraying-coprecipitation method magnetic properties MICROSTRUCTURE
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Preparation and Magnetic Properties of (Fe_7Co_3)_(0.15)(SiO_2)_(0.85)Granular Solids Using the Sol-Gel Method
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作者 Wei CHEN Denglu HOU +4 位作者 Ying LIU Guide TANG Minggang ZHU Jianguo ZHAO Xiangfu NIE and Hongyan WU(Department of Physics, Hebei Normal University, Shijiazhuang 050016, Hebei, China)To whom correspondence should be addressed E-mail: dlhou@hebtu.edu.cn 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1999年第4期389-389,共1页
(Fe7Co3)0.15(SiO2)0.85 granular alloy solid was prepared successfully using sol-gel method. The samples with different reducing temperatures were investigated by X-ray diffractometer(XRD),transmission electron microgr... (Fe7Co3)0.15(SiO2)0.85 granular alloy solid was prepared successfully using sol-gel method. The samples with different reducing temperatures were investigated by X-ray diffractometer(XRD),transmission electron micrography(TEM) and vibrating sample magnetometer(VSM). The av-erage particIe sizes of the samples were also calculated from Scherrer formula. The magnetic properties of (Fe7Co3 )o. 15 (SiO2)0.85 were studied in detail. 展开更多
关键词 SIO2 Fe7Co3 Preparation and magnetic properties of Granular Solids Using the Sol-Gel method
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Magnetic Properties of NiCuZn Ferrite Thin Films Prepared by the Sol-gel Method
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作者 刘锋 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2007年第3期506-509,共4页
Ni0.4Cu0.2Zn0.4Fe2O4 thin films were fabricated on Si substrates by using the sol-gel method and rapid thermal annealing (RTA), and their magnetic properties and crystalline structures were investigated. The samples... Ni0.4Cu0.2Zn0.4Fe2O4 thin films were fabricated on Si substrates by using the sol-gel method and rapid thermal annealing (RTA), and their magnetic properties and crystalline structures were investigated. The samples calcined at and above 600 ℃ have a single-phase spinel structure and the average grain size of the sample calcined at 600 ℃ is about 20 nm. The initial permeability μi, saturation magnetization M and coercivity H of the samples increase with the increasing calcination temperature. The sample calcined at 600 ℃ exhibits an excellent soft magnetic performance, which has μi=33.97 (10 MHz), Hc=15.62 Oe and Ms=228.877 emu/cm^3. Low-temperature annealing can enhance the magnetic properties of the samples. The work shows that using the sol-gel method in conjunction with RTA is a promising way to fabricate integrated thin-film devices. 展开更多
关键词 Ni0.4Cu0.2Zn0.4Fe2O4 thin films sol-gel-method rapid thermal processing magnetic properties
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Preparation and Magnetic Properties of Mn-Zn Ferrites by the Co-precipitation Method 被引量:1
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作者 李雪 张俊喜 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2009年第6期875-878,共4页
Mn-Zn ferrites (Mn1-xZnxFe2O4) with different compositions were prepared by the coprecipitation method, and the influences of such synthesis conditions as pH value, composition and volume ratio (R) of the mixed so... Mn-Zn ferrites (Mn1-xZnxFe2O4) with different compositions were prepared by the coprecipitation method, and the influences of such synthesis conditions as pH value, composition and volume ratio (R) of the mixed solution and NH4HCO3 solution on their microstructures and magnetic properties were discussed. The samples were characterized by X-ray diffraction (XRD) and magnetization measurement instrument. Lattice parameters and average crystalline size of the synthesized materials were calculated from the corresponding XRD patterns with the related software Jade.5. For samples of different pH values, only one phase was found when pH values were 7.0, 8.0 and 9.0. The sample with pH value of 7.0 exhibited the highest saturation magnetic induction, the lowest coercive force, and crystallized best. For samples of different R values with pH value of 7.0, only one phase was observed in all samples, and the sample with R value of 2.3 exhibited the highest saturation magnetic induction and the lowest coercive force. The composition has mainly afected the magnetic properties, and the saturation magnetic induction increases with the increase of the content of Zn (x), but decreases when x is beyond 0.6. The trend of coercive force is on the contrary. However, no magnetism is exhibited when the x value is up to 0.8. 展开更多
关键词 co-precipitation method MICROSTRUCTURE magnetic property Mn-Zn ferrite
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The structural and magnetic properties of barium ferrite powders prepared by the sol-gel method 被引量:1
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作者 Li Jie Zhang Huai-Wu +2 位作者 Li Yuan-Xun Liu Ying-Li Ma Yan-Bing 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第1期467-470,共4页
In this paper, M-type hexagonal barium ferrite powders are synthesized using the sol-gel method. A dried precursor heated in air is analyzed in the temperature range from 50 to 1200 ℃ using thermo-gravimetric analysi... In this paper, M-type hexagonal barium ferrite powders are synthesized using the sol-gel method. A dried precursor heated in air is analyzed in the temperature range from 50 to 1200 ℃ using thermo-gravimetric analysis and differential scanning calorimetry. The effects of the additives and the cacinating temperature on the magnetic properties are investigated, and the results show that single-phase barium ferrite powders can be formed. After heat-treating at 950 ℃ for 4h with 3 wt% additive, the coercivity and saturation magnetization are found to be 440 Oe and 57.9 emu/g, respectively. 展开更多
关键词 barium ferrite sol-gel method POWDER magnetic property
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Influence of two-step cooling method on magnetic properties of Fe_(82)Mo_7B_(10)Cu_1 nanocrystalline alloy 被引量:1
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作者 彭坤 周灵平 +2 位作者 胡爱平 朱家俊 李德意 《中国有色金属学会会刊:英文版》 EI CSCD 2008年第4期852-856,共5页
Soft magnetic properties of Fe82Mo7B10Cu1 nanocrystalline alloy were studied as a function of cooling condition. The results show that higher permeability and relaxation frequency can be obtained by the two-step cooli... Soft magnetic properties of Fe82Mo7B10Cu1 nanocrystalline alloy were studied as a function of cooling condition. The results show that higher permeability and relaxation frequency can be obtained by the two-step cooling method, and the pinning field of the sample obtained by this method is smaller than that of the furnace-cooled and water-quenched samples. This phenomenon was interpreted in terms of internal stress and the magnetic ordering of the residual amorphous phase. The two-step cooling treatment is an effective way to improve the soft magnetic properties of Fe82Mo7B10Cu1 nanocrystalline alloy. 展开更多
关键词 纳米晶合金 两步冷却法 磁性 铁钼硼铜合金
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Microstructure and magnetic properties of NiZn ferrite thin films prepared by sol-gel method
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作者 聂小亮 兰中文 +2 位作者 余忠 孙科 李乐中 《中国有色金属学会会刊:英文版》 CSCD 2007年第A02期854-857,共4页
Ti4+ substitution for Fe3+ in Ni0.5Zn0.5Fe2O4(NZF) ferrite thin films were realized by sol-gel method and annealing at 600 ℃ for 30 min in the air. Crystal structure and lattice constant determination was performed b... Ti4+ substitution for Fe3+ in Ni0.5Zn0.5Fe2O4(NZF) ferrite thin films were realized by sol-gel method and annealing at 600 ℃ for 30 min in the air. Crystal structure and lattice constant determination was performed by X-ray diffractometer(XRD). Surface microstructure was observed by scanning electron microscope(SEM) and atomic force microscope(AFM),and the magnetic properties were measured by vibrating sample magnetometer(VSM). XRD analyses of the samples show that Ni0.5+xZn0.5TixFe2-2xO4(NZTF) films with x varying from 0 to 0.15 in steps of 0.05 are composed of single phase with spinel structure. And the lattice parameter,particle size and the diffraction intensity of the films increase with substitution of Ti as the result of the larger radius ions entering the lattice. SEM and AFM show homogeneous grain size of each sample,but there is a few differences in grain size with different Ti-substitution contents. As the nonmagnetic Ti4+ substitutes Fe3+,both the saturation magnetization and coercivity decrease. 展开更多
关键词 镍锌铁素体薄膜 制备方法 溶胶-凝胶法 微观结构 磁性
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Research on charge ordering and magnetic properties in La_(0.3)Ca_(0.7)Mn_(1-x)W_xO_3 system 被引量:2
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作者 PENG Zhensheng GUO Huanyin +1 位作者 YAN Guoqing MAO Qiang 《Rare Metals》 SCIE EI CAS CSCD 2007年第4期317-322,共6页
The perovskite manganite sample La0.3Ca0.7Mn1-xWxO3 (x = 0.08, 0.12) was prepared by the solid-state reaction method. The effect of W doping on the Mn site to La0.3Ca0.7MnO3 charge ordering phase and the changing pr... The perovskite manganite sample La0.3Ca0.7Mn1-xWxO3 (x = 0.08, 0.12) was prepared by the solid-state reaction method. The effect of W doping on the Mn site to La0.3Ca0.7MnO3 charge ordering phase and the changing process of magnetic properties were studied through the measurement of the M-T curve, M-H curves, and ESR curves of the sample. The results showed that when x = 0.08, the charge ordering (CO) phase exists in the system, the transition temperature Tco= 275 K, and the system exhibits PM when T 〉 275 K. The system transforms from spin-disordering paramagnetism to spin-ordering antiferromagnetism in the charge ordering state with the temperature decreasing from 275 K to 230 K. The long-range antiferromagnetism forms and AFM/CO states coexist between 230 K and 5 K. There is a little ferromagnetic component in the AFM/CO background in a low temperature range. When x = 0.12, the CO phase in the system has almost melted completely. There is a little remnant of the CO phase below 150 K. The system exhibits paramagnetism when T 〉 150 K and transforms from paramagnetism to ferromagnetism when T〈 150 K. 展开更多
关键词 condensed matter physics charge ordering MELTING solid-state reaction method magnetic properties
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Synthesis, characterization and magnetic properties of KFeO_(2) nanoparticles prepared by a simple egg white solution route 被引量:1
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作者 Thongsuk Sichumsaeng Nutthakritta Phromviyo +3 位作者 Supree Pinitsoontorn Pinit Kidkhunthod Narong Chanlek Santi Maensiri 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2022年第1期128-135,共8页
Nanoparticles of potassium ferrite(KFeO_(2))in this work were synthesized by a simple egg white solution method upon calcination in air at 773,873,and 973 K for 2 h.The effects of calcination temperature on the struct... Nanoparticles of potassium ferrite(KFeO_(2))in this work were synthesized by a simple egg white solution method upon calcination in air at 773,873,and 973 K for 2 h.The effects of calcination temperature on the structural and magnetic properties of the synthesized KFeO_(2) nanoparticles were investigated.By varying the calcination temperature,X-ray diffraction and transmission electron microscopy results indicated the changes in crystallinity and morphology including particle size,respectively.Notably,the reduction in particle size of the synthesized KFeO_(2) was found to have a remarkable influence on the magnetic properties.At room temperature,the synthesized KFeO_(2) nanoparticles prepared at 873 K exhibited the highest saturation magnetization(M_(S))of 2.07×10^(4) A·m^(−1).In addition,the coercivity(H_(C))increased from 3.51 to 16.89 kA·m^(−1) as the calcination temperature increased to 973 K.The zero-field cooled(ZFC)results showed that the blocking temperatures(T_(B))of about 125 and 85 K were observed in the samples calcined at 773 and 873 K,respectively.Therefore,this work showed that the egg white solution method is simple,cost effective,and environmentally friendly for the preparation of KFeO_(2) nanoparticles. 展开更多
关键词 egg white solution method potassium ferrite nanoparticles magnetic properties FERROMAGNETISM
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The relativistic density functional investigations on geometries,electronic and magnetic properties of Ir_n (n=1-13) clusters
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作者 郭平 郑继明 +2 位作者 赵佩 郑琳琳 任兆玉 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第8期356-363,共8页
The Ira (n=1-13) clusters are studied using the relativistic density functional method with generalized gradient approximation. A series of low-lying structures with different spin multiplicities have been considere... The Ira (n=1-13) clusters are studied using the relativistic density functional method with generalized gradient approximation. A series of low-lying structures with different spin multiplicities have been considered. It is found that all the lowest-energy Ira (n=4-13) geometries prefer non-compact structures rather than compact structure growth pattern. And the cube structure is a very stable cell for the lowest-energy Ira (n 〉 8) clusters. The second-order difference of energy, the vertical ionization potentials, the electron affinities and the atomic average magnetic moments for the lowest-energy Ira geometries all show odd even alternative behaviours. 展开更多
关键词 density functional method the lowest-energy structures of Irn clusters electronic and magnetic properties
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Fabrication and Investigation of the Magnetic Properties of Co and Co3O4 Nanoparticles
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作者 Fardin Taghizadeh 《Optics and Photonics Journal》 2016年第8期62-68,共8页
The nanoparticles exhibit some novel optical and magnetic properties, which are different from its bulk material. Cobalt oxide has been known as a semi-conductor compound of p type with a Spinel structure. Therefore, ... The nanoparticles exhibit some novel optical and magnetic properties, which are different from its bulk material. Cobalt oxide has been known as a semi-conductor compound of p type with a Spinel structure. Therefore, they are used as gas sensor and absorbent of solar energy. Furthermore, they are employed as an effective catalyzer in environmental clearing. In the thermal gradation method, carbonyl cobalt Co2(CO)8 is often used as a precursor, though cobalt carbonyl is very toxic and expensive. Magnetic compounds have been among interesting issues for human beings for over 4000 years. In large societies, magnetic compounds including computer disks, credit cards, speakers, coolers, automatic doors, and many other devices can be observed on a daily basis. The structure and morphology of as-prepared Co3O4 nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The TEM images showed that the product nanoparticles consisted of dispersive quasi- spherical particles with a narrow size distribution ranged from 5 to 15 nm and an average size around 10 nm. The magnetic measurements confirmed that the Co3O4 nanoparticles show a little ferromagnetic behavior which could be attributed to the uncompensated surface spins and finite size effects. The ferromagnetic order of the Co3O4 nanoparticles is raised with increasing the decomposition temperature. 展开更多
关键词 magnetic properties Nano Particles Fabrication method CO3O4
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Synthesis and Soft Magnetic Properties of Mg-doped Ni Nanoparticles
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作者 YANG Jing-hai FENG Bo +5 位作者 LIU Yang ZHANG Yong-jun YANG Li-li WANG Ya-xin LANG Ji-hui WANG Dan-dan 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2008年第5期534-536,共3页
Mg-doped Ni nanoparticles with good soft magnetic properties were prepared with the sol-gel method and were sintered at 400, 500, 600, and 900℃ in argon atmosphere, respectively. The structure and magnetic properties... Mg-doped Ni nanoparticles with good soft magnetic properties were prepared with the sol-gel method and were sintered at 400, 500, 600, and 900℃ in argon atmosphere, respectively. The structure and magnetic properties of the samples were studied by means of X-ray diffraction, TEM, and VSM magnetometers. X-Ray powder diffraction results show that Ni-Mg solid solution was formed with the single phase of face-centered cubic(fcc) structure. The particle size became larger with the increase of temperature. When the sintering temperature was 400 °C, the particle size was 6.3 nm, whereas it was 46.2 nm at 900 °C. Both the saturation magnetization(Ms) and the coercivity were enhanced with the increase of the particle size. The Ms values of the samples ranged from 18.965 to 46.766 emu/g and the coercivity ranged from 1051.3568 to 9145.0848 A/m. 展开更多
关键词 Mg NI NANOPARTICLES Soft magnetic property Sol-gel method
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Magnetic Properties of One-Dimensional Ferromagnetic Mixed-Spin Model within Tyablikov Decoupling Approximation
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作者 陈渊 项颖 宋闯闯 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第10期747-752,共6页
In this paper, we apply the two-time Green's function method, and provide a simple way to study themagnetic properties of one-dimensional spin-(S, s) Heisenberg ferromagnets.The magnetic susceptibility and correla... In this paper, we apply the two-time Green's function method, and provide a simple way to study themagnetic properties of one-dimensional spin-(S, s) Heisenberg ferromagnets.The magnetic susceptibility and correlationfunctions are obtained by using the Tyablikov decoupling approximation.Our results show that the magnetic susceptibilityand correlation length are a monotonically decreasing function of temperature regardless of the mixed spins.It isfound that in the case of S = s, our results of one-dimensional mixed-spin model is reduced to be those of the isotropicferromagnetic Heisenberg chain in the whole temperature region.Our results for the susceptibility are in agreement withthose obtained by other theoretical approaches. 展开更多
关键词 magnetic property Green's function method mixed-spin model Tyablikov decoupling approximation
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Crystallization Kinetics and Magnetic Properties of Fe<sub>40</sub>Ni<sub>40</sub>B<sub>20</sub>Bulk Metallic Glass
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作者 Nasr-Eddine Chakri Badis Bendjemil M. Baricco 《Advances in Chemical Engineering and Science》 2014年第1期36-38,共3页
Fe-based bulk metallic glasses (BMGs) have been extensively studied due to their potential technological applications and their interesting physical properties such as a low modulus of elasticity, high yielding stress... Fe-based bulk metallic glasses (BMGs) have been extensively studied due to their potential technological applications and their interesting physical properties such as a low modulus of elasticity, high yielding stress and good magnetic properties. In the present work, the bulk metallic glass (BMG) formation of Fe40Ni40B20 (numbers indicate at %) with a ribbon form was fabricated by the single roller melt-spinning method. Rapid solidification leads to a fully amorphous structure for all compositions. The thermal properties associated with crystallization temperature of the glassy samples were measured using differential scanning calorimetry (DSC) at a heating rate of 10℃/mn. The microstructure and constituent phase of the alloy composite have been analyzed by using X-ray diffractometry (XRD). The effect of high temperature on the isothermal crystallization of Fe40Ni40B20 ribbon was investigated by HTX-ray diffraction. In addition, these ribbon glasses also exhibit good soft magnetic properties with M-H curvature measured under the magnetic fields between –1 kOe and 1 kOe. 展开更多
关键词 Bulk Metallic GLASSES DSC XRD method HTX magnetic properties
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Structural and Magnetic Properties of Cr-Co Nanoferrite Particles
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作者 Mamilla Lakshmi Katrapally Vijaya Kumar Krishnan Thyagarajan 《Advances in Nanoparticles》 2016年第1期103-113,共11页
Nano-crystalline Cr<sub>x</sub>CoFe<sub>2–x</sub>O<sub>4</sub> (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) ferrites were synthesized by sol-gel method. The X-ray diffraction patterns of all t... Nano-crystalline Cr<sub>x</sub>CoFe<sub>2–x</sub>O<sub>4</sub> (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) ferrites were synthesized by sol-gel method. The X-ray diffraction patterns of all the samples provide information about the existence of single phase spinel structure. The SEM and TEM micrographs show the uniform particle distribution and SAED pattern represents the polycrystalline nature of the resultant ferrite nano-particles. High purity of the sample is confirmed by energy dispersive X-ray analysis. The FTIR spectra show two strong absorption bands in the range of 600 - 400 cm<sup>–1</sup>, which confirm the presence of M-O stretching band in ferrites. The magnetic properties of the synthesized samples were investigated by using vibrating sample magnetometer at room temperature. According to VSM reports the main magnetic parameters like saturation magnetization (M<sub>s</sub>), coercivity (H<sub>c</sub>) were found to decrease with the substitution of Cr<sup>3+</sup> content. Possible mechanisms which are responsible for the results are scrutinized minutely in this paper. 展开更多
关键词 Sol-Gel method magnetic Property Cr-Co Nanoferrite Particles
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Magnetic properties of samarium and gadolinium co-doping Mn-Zn ferrites obtained by sol-gel auto-combustion method 被引量:7
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作者 季必发 田长安 +4 位作者 张全争 吉冬冬 阳杰 谢劲松 司靖宇 《Journal of Rare Earths》 SCIE EI CAS CSCD 2016年第10期1017-1023,共7页
Mn-Zn ferrites doped with different contents of Sm^(3+) and Gd^(3+) ions were prepared by sol-gel auto-combustion method and characterized by Fourier transform infrared spectroscopy(FTIR), thermogravimetric an... Mn-Zn ferrites doped with different contents of Sm^(3+) and Gd^(3+) ions were prepared by sol-gel auto-combustion method and characterized by Fourier transform infrared spectroscopy(FTIR), thermogravimetric analysis(TG), X-ray diffraction(XRD), scanning electron microscopy(SEM) and vibrating sample magnetometer(VSM). When samples were calcined in a relatively low temperature below 1100 °C, secondary phases(α-Fe_2O_3) could be identified. Therefore, in order to acquire pure and better crystallinity, the suitable calcining temperature of powders was selected at 1200 °C. It was also found that all the samples consisting of ferrite phases of typical spinel cubic structure and average crystallite sizes between 31.5 and 38.2 nm were obtained after calcining at 1200 oC for 4 h. The lattice parameters increased almost linearly with increasing Sm content. A dense microstructure was obtained after sintering at 1250 °C for 4 h. Through the analysis of magnetic properties, hysteresis loops for all the samples were narrow with low values of coercivity and retentivity, indicating the paramagnetic nature of these samples. And saturation magnetization Ms strongly depended on the type of additive to reach a maximum of 47.99 emu/g for x=0.015, which showed a great promise for hyperthermia applications. 展开更多
关键词 Mn-Zn ferrites co-doping sol-gel auto-combustion method microstructure magnetic properties rare earths
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Magnetic properties and magnetic entropy change of perovskite manganites La_(0.9-x)Eu_xSr_(0.1)MnO_3(x=0.000,0.075) by experimental method and numerical fitting 被引量:4
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作者 Xiang Jin Jianjun Zhao +8 位作者 Hongye Wu Bao Xu Yunbin Sun Xiaodong Sun Fengze Cao Kai Wang Wenxing Wang Yutong Zhang Yi Lu 《Journal of Rare Earths》 SCIE EI CAS CSCD 2019年第6期622-627,共6页
Polycrystalline samples La_(0.9-x)EuxSr_(0.1)MnO_3(x = 0.000, 0.075) were prepared by the standard solid-state reaction method. The results show that the samples preform a characteristic of clusters spin-glass state a... Polycrystalline samples La_(0.9-x)EuxSr_(0.1)MnO_3(x = 0.000, 0.075) were prepared by the standard solid-state reaction method. The results show that the samples preform a characteristic of clusters spin-glass state at low temperature. The samples show a characteristic of ferromagnetism(FM) characteristic in the temperature range of 15-125 K and 15-150 K respectively; the samples show preformed clusters in the temperature range of 125-343 K and 150-325 K, respectively, the samples show paramagnetism(PM)characteristic above 343 and 325 K, respectively. The second-order transitions are found at 118 and 135 K for undoped and doped sample, respectively. When the applied magnetic field is 7 T, the maximum magnetic entropy change |△S_M| value of the samples is near the Curie temperature(Tc), and the value of|△S_M| reaches 2.76 and 3.03 J/(K kg), respectively. In addition, the relative cooling power(RCP) is found to be 425.28 and 443.53 J/kg. The numerical fitting data fit well with experimental data. These results indicate that both the samples have the potential to realize magnetic refrigeration in the high temperature region(T > 77 K). 展开更多
关键词 PEROVSKITE magnetic properties magnetic entropy change Preforming cluster phase Least SQUARE method RARE earths
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Backfill support's backfill and operation properties and evaluation 被引量:4
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作者 ZHANG Qiang DU Chang-long +3 位作者 ZHANG Ji-xiong WANG Jia-qi LI Meng QI Wen-yue 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第6期1524-1534,共11页
To ensure compacted backfilling, it is essential to ensure the reliability of the performance of a solid backfill support, key equipment for integrating backfilling and mining. To evaluate the backfilling performance ... To ensure compacted backfilling, it is essential to ensure the reliability of the performance of a solid backfill support, key equipment for integrating backfilling and mining. To evaluate the backfilling performance of a backfill support, the concept of backfill and operation properties is proposed in this study. Moreover, it is elaborated in terms of five aspects, namely, structural property, supporting property, tamping property, mechanical response property, and geological adaptation property, which are specifically reflected by 14 indexes including the supporting intensity and vertical roof gap. Seven separate evaluation indexes are selected to build a backfill and operation properties based system for evaluating the design schemes of the backfill support via a multi-index comprehensive evaluation method; then, the evaluation method and process together with measures to control the backfill and operation properties are proposed. By using this system, 11 schemes for optimizing the ZC5200/14.5/3 backfill support at Zhaizhen Coal Mine are evaluated, and scheme #10 is found to show superior vertical roof gap and other backfill and operation properties, thus demonstrating the reasonability of the evaluation system. On this basis, the backfill support research framework of designing initial scheme, optimizing design scheme, selecting the best evaluation indexes, evaluating optimizing scheme, and evaluating operation properties is built; this should serve as an important reference for further studies on the roof controlling performance of a backfill support. 展开更多
关键词 backfilling coal mining backfill and operation properties tamping force vertical roof gap horizontal roofgap evaluation method
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Oxygen content and magnetic properties of composites La_(0.75)Sr_(0.25)MnO_(3±δ) dcalcined at different temperatures 被引量:3
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作者 Deng-Hui Ji Xue Hou +3 位作者 Gui-De Tang Zhuang-Zhi Li Deng-Lu Hou Ming-Gang Zhu 《Rare Metals》 SCIE EI CAS CSCD 2014年第4期452-458,共7页
The effects of the calcination temperature on the oxygen content and magnetic properties of the nano- crystalline perovskite manganite Lao.75Sro.25MnO3±δ pre- pared by the sol-gel method were investigated. The h... The effects of the calcination temperature on the oxygen content and magnetic properties of the nano- crystalline perovskite manganite Lao.75Sro.25MnO3±δ pre- pared by the sol-gel method were investigated. The highest temperatures at which the samples were calcined were 973, 1073, 1273, and 1473 K. The X-ray diffraction (XRD) analyses indicate that all the samples have only a single phase with the R3c perovskite structure. As the calcination temperature and calcination time increase, the oxygen content in the samples increases from being deficient to being in excess of that in the stoichiometric formula. The crystallite size also increases from 23 to 283 nm. Magnetic measurements indicate that the sample calcined at 1073 K has the highest Curie temperature. This is owing to the fact that the crystallite cores of this sample have stoichiometric oxygen content. The dependence of the Curie temperature and the saturation magnetization on the calcination tem- perature are successfully explained. 展开更多
关键词 Perovskite manganite magnetic property Oxygen content Sol-gel method
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Magnetic Properties of Thermally Aged Fe-Cu Alloys with Pre-deformation 被引量:2
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作者 Yi LI Yuan-fei LI +3 位作者 Ben XU Qiu-lin LI Guo-gang SHU Wei LIU 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2016年第9期981-987,共7页
Magnetic properties of thermally aged Fe-Cu alloys with pre deformation have been evaluated to improve the understanding of using magnetic technology for the nondestructive evaluation (NDE) of irradiation embrittlem... Magnetic properties of thermally aged Fe-Cu alloys with pre deformation have been evaluated to improve the understanding of using magnetic technology for the nondestructive evaluation (NDE) of irradiation embrittlement in reactor pressure vessel (RPV) steels. Fe-Cu alloys with and without pre-deformation were thermally aged at 500 ℃ and the changes in microstructure, mechanical properties and magnetic properties were determined. It is found that the strain-induced dislocations recover and the Cu-rich particles precipitate during the aging process, and the magnet- ic properties variation depends on the combined influence of these two factors. From the point of view of NDE, a fully tempered or annealed microstructure is favorable before RPV is put into service. These results improve the un- derstanding of magnetic property evolution in actual RPV steels and help to develop NDE theory for irradiation embrittlement. 展开更多
关键词 RPV steel nondestructive evaluation magnetic property Cu-rich precipitate DISLOCATION
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