The Co content dependence of crystal structure and specific magnetization of Fe1-xCox-SiO2granular solid prepared by the sol-gel method have been studied. It is found that the crystal structure, Iattice parameter and ...The Co content dependence of crystal structure and specific magnetization of Fe1-xCox-SiO2granular solid prepared by the sol-gel method have been studied. It is found that the crystal structure, Iattice parameter and specific magnetization of the FeCo alloy particles depend on the Co content.展开更多
High-entropy materials(HEMs)have better mechanical,thermal,and electrical properties than traditional materials due to their special"high entropy effect".They can also adjust the performance of high entropy ...High-entropy materials(HEMs)have better mechanical,thermal,and electrical properties than traditional materials due to their special"high entropy effect".They can also adjust the performance of high entropy ceramics by adjusting the proportion of raw materials,and have broad application prospects in many fields.This article provides a review of the high entropy effect,preparation methods,and main applications of high entropy ceramic materials,especially exploring relevant research on high entropy perovskite ceramics.It is expected to provide reference for the promotion of scientific research and the development of further large-scale applications of high-entropy ceramic materials.展开更多
Bulk polycrystalline samples of La0.60Sr0.4MnO3 and La0.60Sr0.25-yNa0.15ΔyMnO3 with 0.00≤y≤0.15 (“Δ” representing cation vacancy) were successfully synthesized using the sol-gel method. The structural, magnetic,...Bulk polycrystalline samples of La0.60Sr0.4MnO3 and La0.60Sr0.25-yNa0.15ΔyMnO3 with 0.00≤y≤0.15 (“Δ” representing cation vacancy) were successfully synthesized using the sol-gel method. The structural, magnetic, and electrical properties of the polycrystalline of the samples were investigated. The results of X-ray powder diffraction patterns show that these compounds crystallize in a distorted rhombohedral structure with the space group R3C. The measurement shows that, with vacancy content y increasing, the unit cell volume V of samples increases, furthermore, the Curie temperature TC decreases. The temperature dependence of resistivity shows that all samples undergo a metal-semiconductor transition accompanying a ferromagnetic to paramagnetic transition with the increase of temperature. Under an applied filed of 1.8 T, a maximum room temperature magnetoresistance (MR) of 20% is obtained at 293 K for the compound La0.60Sr0.1Na0.15Δ0.15MnO3. The MR peak value of La0.60Sr0.1Na0.15Δ0.15MnO3 increases 2 times more than that of La0.60Sr0.40MnO3 (MRP=6.4%, TMR=373 K), and the MR peak is shifted from 373 K to room temperature.展开更多
本文利用溶胶凝胶法，成功制备了名义成分为La0.75Sr0.25Mn1-xO3（x=0．00，0．03，0．05，0．08，0．10，0．13，0．15，0．17）的含有B位空位的钙钛矿样品，最高煅烧温度为1073K．利用软件X Pert High Score Plus对样品的XRD图谱进行...本文利用溶胶凝胶法，成功制备了名义成分为La0.75Sr0.25Mn1-xO3（x=0．00，0．03，0．05，0．08，0．10，0．13，0．15，0．17）的含有B位空位的钙钛矿样品，最高煅烧温度为1073K．利用软件X Pert High Score Plus对样品的XRD图谱进行分析，当x≤0．08的样品为钙钛矿单相，其余样品含有次相镧的氧化物，说明B位空位存在最大值，0．08〈zm〈0．10；磁性测量结果说明B位空位含量的增加一方面增加了Mnt＋含量，另外一方面阻碍了Mn3＋-O2-Mn4＋双交换作用．展开更多
文摘The Co content dependence of crystal structure and specific magnetization of Fe1-xCox-SiO2granular solid prepared by the sol-gel method have been studied. It is found that the crystal structure, Iattice parameter and specific magnetization of the FeCo alloy particles depend on the Co content.
文摘High-entropy materials(HEMs)have better mechanical,thermal,and electrical properties than traditional materials due to their special"high entropy effect".They can also adjust the performance of high entropy ceramics by adjusting the proportion of raw materials,and have broad application prospects in many fields.This article provides a review of the high entropy effect,preparation methods,and main applications of high entropy ceramic materials,especially exploring relevant research on high entropy perovskite ceramics.It is expected to provide reference for the promotion of scientific research and the development of further large-scale applications of high-entropy ceramic materials.
基金This work was financially supported by the National Natural Science Foundation of China (No.NSF-10074016), the Natural Science Foundation of Hebei Province (No.E2006000168) and Science Foundation of Hebei Education Department (No.2005358).
文摘Bulk polycrystalline samples of La0.60Sr0.4MnO3 and La0.60Sr0.25-yNa0.15ΔyMnO3 with 0.00≤y≤0.15 (“Δ” representing cation vacancy) were successfully synthesized using the sol-gel method. The structural, magnetic, and electrical properties of the polycrystalline of the samples were investigated. The results of X-ray powder diffraction patterns show that these compounds crystallize in a distorted rhombohedral structure with the space group R3C. The measurement shows that, with vacancy content y increasing, the unit cell volume V of samples increases, furthermore, the Curie temperature TC decreases. The temperature dependence of resistivity shows that all samples undergo a metal-semiconductor transition accompanying a ferromagnetic to paramagnetic transition with the increase of temperature. Under an applied filed of 1.8 T, a maximum room temperature magnetoresistance (MR) of 20% is obtained at 293 K for the compound La0.60Sr0.1Na0.15Δ0.15MnO3. The MR peak value of La0.60Sr0.1Na0.15Δ0.15MnO3 increases 2 times more than that of La0.60Sr0.40MnO3 (MRP=6.4%, TMR=373 K), and the MR peak is shifted from 373 K to room temperature.
文摘本文利用溶胶凝胶法，成功制备了名义成分为La0.75Sr0.25Mn1-xO3（x=0．00，0．03，0．05，0．08，0．10，0．13，0．15，0．17）的含有B位空位的钙钛矿样品，最高煅烧温度为1073K．利用软件X Pert High Score Plus对样品的XRD图谱进行分析，当x≤0．08的样品为钙钛矿单相，其余样品含有次相镧的氧化物，说明B位空位存在最大值，0．08〈zm〈0．10；磁性测量结果说明B位空位含量的增加一方面增加了Mnt＋含量，另外一方面阻碍了Mn3＋-O2-Mn4＋双交换作用．
