排序方式: 共有9条查询结果,搜索用时 15 毫秒
1
1.
2.
The variation of Mn-dopant distribution state with x and its effect on the magnetic coupling mechanism in Znl-xMnxO nanocrystals 下载免费PDF全文
Zn1-xMnxO (x = 0.0005, 0.001, 0.005, 0.01, 0.02) nanocrystals are synthesized by using a wet chemical process. The coordination environment of Mn is characterized by X-ray photoelectron spectroscopy, Raman spectroscopy, and its X-ray absorption fine structure. It is found that the solubility of substitutional Mn in a ZnO lattice is very low, which is less than 0.4%. Mn ions first dissolve into the substitutional sites in the ZnO lattice, thereby forming Mn2+O4 tetrahedral coordination when x ≤ 0.001, then entering into the interstitial sites and forming Mn3+O6 octahedral coordination when x ≥ 0.005. All the samples exhibit paramagnetic behaviors at room temperature, and antiferromagnetic coupling can be observed below 100 K. 相似文献
3.
窦士学 《高等学校化学学报》1982,3(4):502-508
应用Folry的缩聚理论处理铝酸盐型熔体(MO-Al2O3),得到了聚合阴离子的分布函数。通过缩聚反应平衡常数可将混合自由能和组元活度表达为熔体组成的函数。预期了产生凝胶化的条件。由模型所得理论曲线与实验结果进行了比较。 相似文献
4.
5.
Manipulating coupling state and magnetism of Mn-doped ZnO nanocrystals by changing the coordination environment of Mn via hydrogen annealing 下载免费PDF全文
Mn-doped ZnO nanocrystals are synthesized by a wet chemical route and treated in H_2/Ar atmosphere with different H_2/Ar ratios.It is found that hydrogen annealing could change the coordination environment of Mn in ZnO lattice and manipulate the magnetic properties of Mn-doped ZnO.Mn ions initially enter into interstitial sites and a Mn~(3+)O_6 octahedral coordination is produced in the prepared Mn-doped ZnO sample,in which the nearest neighbor Mn~(3+) and O~2 ions could form a Mn~(3+)-O~(2-)-Mn~(3+) complex.After H_2 annealing,interstitial Mn ions can substitute for Zn to generate the Mn~(2+)O_4tetrahedral coordination in the nanocrystals,in which neighboring Mn~(2+) ions and H atoms could form a Mn~(2+)-O~(2-)-Mn~(2+)complex and Mn-H-Mn bridge structure.The magnetic measurement of the as-prepared sample shows room temperature paramagnetic behavior due to the Mn~(3+)-O~(2-)-Mn~(3+) complex,while the annealed samples exhibit their ferromagnetism,which originates from the Mn-H-Mn bridge structure and the Mn-Mn exchange interaction in the Mn~(2+)-O~(2-)-Mn~(2+)complex. 相似文献
6.
7.
8.
9.
The variation of Mn-dopant distribution state with x and its effect on the magnetic coupling mechanism in Zn_(1-x) Mn_x O nanocrystals 下载免费PDF全文
Zn1-x Mn x O(x = 0.0005,0.001,0.005,0.01,0.02) nanocrystals are synthesized by using a wet chemical process.The coordination environment of Mn is characterized by X-ray photoelectron spectroscopy,Raman spectroscopy,and its X-ray absorption fine structure.It is found that the solubility of substitutional Mn in a ZnO lattice is very low,which is less than 0.4%.Mn ions first dissolve into the substitutional sites in the ZnO lattice,thereby forming Mn2+O4tetrahedral coordination when x ≤ 0.001,then entering into the interstitial sites and forming Mn3+O6octahedral coordination when x ≥ 0.005.All the samples exhibit paramagnetic behaviors at room temperature,and antiferromagnetic coupling can be observed below 100 K. 相似文献
1