晶体和磁性结构和BiMnO ((3+delta) 的特性
Alexei A Belik1, Katsuaki Kodama, Naoki Igawa
1International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan. Alexei.BELIK@nims.go.jp
Journal of the American Chemical Society
|May 22, 2010
概括
晶体和磁性结构的比斯木 manganite (BiMnO(3+delta)) 使用中子衍射确定. 氧含量 (三角形) 影响晶体对称性,磁性排序和磁矩大小,其中BiMnO{3.14) 呈现出旋转玻璃状态.
科学领域:
- 固态化学 固态化学
- 材料科学 材料科学 材料科学
- 晶体学 晶体学是指结晶学.
- 磁力学 磁力学 是一种
背景情况:
- 石棉矿 (BiMnO(3+delta)) 是一种具有复杂晶体和磁性结构的材料.
- 众所周知,矿矿的性质对氧气固体测量和缺陷敏感.
研究的目的:
- 为了确定BiMnO的晶体和磁性结构(3+delta) 对于不同的氧含量 (delta = 0.03,0.08,0.14).
- 研究氧气固体测量对结构对称性,磁性排序和磁矩的影响.
- 为了比较BiMnO(3+delta) 的性能与相关的色矿 (LaMnO(3+delta)) 的性能.
主要方法:
- 在低温 (8-10 K) 和室温 (290 K) 收集的中子衍射数据的瑞特维尔德精细化.
- 分析晶体结构,包括空间组的确定和晶格参数.
- 确定磁性结构,磁性排序温度 (T) 和精细的磁矩.
主要成果:
- BiMnO ((3.03) 和BiMnO ((3.08) 在单临床系统中结晶 (C2 / c和P2 ((1) / c),分别表现出低于82 K和68 K的铁磁性,其磁矩在10 K时为2.88 ((2) μB和2.33 ((2) μB.
- Mn空缺位于特定的位置,可能导致观察到的晶体对称性变化.
- BiMnO(3.14) 结晶在一个正方体系统 (Pnma) 中,并表现出一个自旋玻璃的磁性状态,没有磁性排序到8K.
结论:
- 晶体结构的系统变化,磁性排序和BiMnO的磁性属性 ((3+delta) 强烈依赖氧含量 (delta).
- 建议空缺订单和收费订单作为观察到的结构转型的机制.
- 该研究提供了BiMnO(3+delta的详细结构和磁性表征,突出了其与氧气固体测量的可调性.
更多相关视频
07:42Optimizing Magnetic Force Microscopy Resolution and Sensitivity to Visualize Nanoscale Magnetic Domains
Published on: July 20, 2022
06:49Radio Frequency Magnetron Sputtering of GdBa2Cu3O7−δ/ La0.67Sr0.33MnO3 Quasi-bilayer Films on SrTiO3 (STO) Single-crystal Substrates
Published on: April 12, 2019
相关概念视频
03:02Colors and Magnetism
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
02:22Structures of Solids
Solids in which the atoms, ions, or molecules are arranged in a definite repeating pattern are known as crystalline solids. Metals and ionic compounds typically form ordered, crystalline solids. A crystalline solid has a precise melting temperature because each atom or molecule of the same type is held in place with the same forces or energy. Amorphous solids or non-crystalline solids (or, sometimes, glasses) which lack an ordered internal structure and are randomly arranged. Substances that...
02:42Valence Bond Theory
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
02:58Crystal Field Theory - Octahedral Complexes
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
02:42Ionic Crystal Structures
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...