Journal of Materials Science
Mn(3+x) Ga(1-x) N compounds with x = 0.0 and 0.1 were prepared by re-sintering Mn(2)N(0.86), Ga bulk and Mn powders. These compounds are deduced to be the N-deficiency ones. In Mn(3)GaN, a step-like magnetic transition, from frustrated antiferromagnetism to paramagnetism with increasing temperature, occurs at 370 K, while the same magnetic transition of Mn(3.1)Ga(0.9)N is far above 380 K. The enhanced magnetization of Mn(3)GaN at low temperatures is ascribed to the fast lowering of antiferromagnetism. The electrical resistivity of Mn(3)GaN exhibits a typically metallic conducting behavior with a positive magnetoresistance of 4-7%.
关键词:
perovskites;heat;manganese;mn3znn;phase
Materials Science-Poland
Mn(4-x)Ag(x)N compounds (x = 0.0, 0.3, 0.6, 1.0) were prepared by milling and subsequently annealing the mixture of Mn(2)N(0.86), Mn, and Ag powders. All compounds display good single-phase characteristics. Both Mn(4)N and Mn(3.7)Ag(0.3)N exhibit ferrimagnetism, and a little Ag replacement of Mn can improve the saturation magnetization. The magnetic transition of Mn(3.4)Ag(0.6)N and Mn(3)AgN below 15 K is from triangular antiferromagnetism to non-coplanar ferrimagnetism, while the ones at 256 and 275 K (Mn(3.4)Ag(0.6)N and Mn(3)AgN, respectively) have been ascribed to the gradual transition, as temperature increases, from the triangular antiferromagnetic structure Gamma(5g) to a ferrimagnetic-like one. Two minima appear on the rho(T) curves for Mn(3)AgN, with the observation of a positive magnetoresistance throughout the whole tempeature-dependent change.
关键词:
antiferromagnetism;spin reorientation;magnetoresistance;metallic perovskite-type;mn4n;manganese;antiferromagnet;phase
Journal of Physical Chemistry C
The highly unusual structural and electronic properties of the alpha-phase of (Si(1-x)C(x))(3)N(4) are determined by density functional theory (DFT) calculations using the Generalized Gradient Approximation (GGA). The electronic properties of alpha-(Si(1-x)C(x))(3)N(4) are found to be very close to those of alpha-C(3)N(4). The bandgap of alpha-(Si(1-x)C(x))(3)N(4) significantly decreases as C atoms are substituted by Si atoms (in 2 most cases, smaller than that of either alpha-Si(3)N(4) or alpha-C(3)N(4)) and attains a minimum when the ratio of C to Si is close to 2. On the other hand, the bulk modulus of alpha-(Si(1-x)C(x))(3)N(4) is found to be closer to that of alpha-Si(3)N(4) than of alpha-C(3)N(4). Plasma-assisted synthesis experiments of CN(x) and SiCN films are performed to verify the accuracy of the DFT calculations. TEM measurements confirm the calculated lattice constants, and FT-IR/XPS analysis confirms the formation and lengths of C-N and Si-N bonds. The results of DFT calculations are also in a remarkable agreement with the experiments of other authors.
关键词:
chemical-vapor-deposition;silicon-carbon nitride;thin-films;optical-properties;room-temperature;alpha-phase;growth;hard;photoluminescence;microstructure
YANG Jilian ZHANC Baisheng DINC Yongfan China Institute of Atomic Engergy
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Beijing
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ChinaYANG Yingchang ZHANG Xiaodong Peking University
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Beijing
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ChinaPAN Shuming General Research Institute for Non-Ferrous Metals
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Beijing
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China associate professor
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P.O.Box 275
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Branch No.30
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Beijing 102413
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China
金属学报(英文版)
The N occupying sites and magnetic structures in R_2Fe_(17)N_x(R=Y,Dy,Nd)are de- termined by neutron diffraction.The effects of the site occupation of N on magnetic properties are discussed primarily.
关键词:
neutron diffraction
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null
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null
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null
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null
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null
Materials and Corrosion-Werkstoffe Und Korrosion
A CrN/Cr(1-x)Al(x)N coating comprised of an inner layer of CrN and an outer layer of Cr1(1-x)Al(x)N with a gradient distribution of Al was deposited on two different alloys by a reactive sputtering method. Oxidation and hot-corrosion tests of the gradient CrN/Cr1(1-x)Al(x)N coating were performed at different temperatures. The phase compositions and morphologies of the as-deposited coating and the corrosion products were investigated by using XRD and SEM/EDS. The results showed that the gradient CrN/Cr1(1-x)Al(x)N coating exhibited good oxidation resistance at temperatures above 1000 degrees C owing to the formation of an alpha-Al(2)O(3)-rich oxide scale. The coating possessed good hot-corrosion resistance in molten sulfate because the inner CrN layer could supply enough Cr to form a relatively protective Cr(2)O(3) after the Al(2)O(3)-enriched scale failed due to its dissolution in the molten sulfate.
关键词:
high-temperature oxidation;aluminide coatings;overlay coatings;nitride coatings;behavior;alloy;superalloy;k38g;cr
杨继廉
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张百生
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丁永凡
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杨应昌
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张晓东
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潘树明
金属学报
用中子衍射法测定了R_2Fe_(17)N_x(R=Y,Dy,Nd)中N的占位及磁结构,初步讨论了N的占位对磁性能的影响
关键词:
中子衍射
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Curie temperature
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permanent magnet
万斌
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陈鸣波
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周细应
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王伟
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李文戈
无机材料学报
doi:10.3724/SP.J.1077.2010.00285
在0.5wt%NaF+1mol/L Na_2SO_4溶液中,20V电压下,通过阳极氧化的方法,在纯Ti片表面制备出与基底垂直、排列整齐有序的TiO_2纳米管,将制得的TiO_2纳米管在500℃、氨气的气氛下退火2h,然后,在0.5mol AgNO_3溶液中用12W的紫外灯照射24h,制备出Ag/TiO_(2-x)N_x纳米管,并用XRD,SEM和XPS进行表征.实验结果显示,在紫外光下,Ag/TiO_(2-x)N_x纳米管的光电催化降解效率比TiO_2纳米管的光电催化降解效率提高了39.68%;在可见光下,Ag/TiO_(2-x)N_x纳米管的光电催化降解效率比TiO_(2-x)N_x纳米管可见光光电催化的降解效率提高了12%.可见光光电催化16h后,初始浓度为10×10~(-6)mol/L的亚甲基蓝降解率达到50.53%.
关键词:
阳极氧化
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TiO_2
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纳米管
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掺杂
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光电催化降解
李万俊
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孔春阳
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秦国平
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阮海波
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杨天勇
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梁薇薇
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孟祥丹
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赵永红
材料导报
获得高质量稳定的p型ZnO薄膜是实现ZnO基光电器件化的关键.目前,国际上公认V族元素中的N替代O位(No)是实现p型ZnO较理想的掺杂途径.但p-ZnO:N薄膜的导电性能会随着时间、光照、温度条件发生变化,稳定性不足.大量的理论和实验研究表明N基二元共掺( N-X)可以提高N在ZnO薄膜中的固溶度,浅化N的受主能级,且在很大程度上能够改善p型ZnO的导电性能,有利于获得稳定的p型ZnO薄膜.为此,从N基施主受主共掺、双受主共掺以及其它共掺方面综述了N-X共掺p型ZnO薄膜的研究现状.
关键词:
p型ZnO薄膜
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N-X共掺
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稳定性
