準二次元のLa2Co2O3Se2における直角なスピン配列
Yayoi Fuwa1, Takashi Endo, Makoto Wakeshima
1Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan.
Journal of the American Chemical Society
|December 4, 2010
まとめ
研究者は,La(2)Co(2)O(3)Se(2) の結晶,電子,磁気構造を調査しました. 彼らは200K以下のコバルトイオンに非コリネア反鉄磁性構造を発見し,c平面に直角モメントを持つ.
科学分野:
- 固体化学 固体化学
- マテリアルサイエンス 材料科学
- 凝縮物質物理学 凝縮物質物理学
背景:
- コバルトオキシセレニドは,電子と磁気における潜在的な応用を持つ新興の材料です.
- 結晶構造,電子構成,磁気順序の相互作用を理解することは,新しい機能的材料の設計に不可欠です.
研究 の 目的:
- コバルトオキシセレニドLa(2)Co(2)O(3)Se(2) の結晶,電子,磁気構造を解明する.
- コバルトイオンの磁気配列を調査し,磁気モメントを決定する.
主な方法:
- 粉末中性子 difrraction 測定は,結晶と磁気構造を決定するために使用されました.
- コバルトイオンの電子性質と電子状態を理解するために,帯状構造の計算を行った.
主要な成果:
- La(2) Co(2) O(3) Se(2) は四角形の層構造 (空間群I4/mmm) で結晶化する.
- バンド構造の計算は,コイオンに対する二価高スピン状態を示している.
- ニュートロン difraktionは200K以下の伝播ベクトル k = (1⁄2, 1⁄2, 0) の非コリネア反鉄磁気構造を明らかにしました.
- オーダーされた磁気モーメントは10Kで3.5μ(B) で,近隣のCモーメントはc平面に直角であることが判明した.
結論:
- この研究は,La(2)Co(2)O(3)Se(2) の構造,電子,磁気特性に関する包括的な理解を提供します.
- 特定された非コリネア反鉄磁性構造は,このコバルト酸化セレニド系における複雑な磁気相互作用を強調しています.
- これらの発見は,層層の移行金属酸化物とセレニドの基本的な知識に貢献し,将来の材料設計の道を開く.
関連する概念動画
03:06The Pauli Exclusion Principle
The arrangement of electrons in the orbitals of an atom is called its electron configuration. We describe an electron configuration with a symbol that contains three pieces of information:
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...
02:42Ionic 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...
04:01VSEPR Theory and the Effect of Lone Pairs
Effect of Lone Pairs of Electrons on Molecule Geometry
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
01:27Symmetry Elements in a Crystal
Crystal symmetry operations are isometric transformations that map objects onto indistinguishable copies while preserving distances, angles, and volumes. The simplest symmetry operation is translation, which shifts the entire infinite crystal lattice parallelly by a translation vector.Crystallographic rotations involve rotations by an angle of 2π/n around an axis without changing the positions of points on the axis. It is called the rotational axis of the symmetry, denoted by n. The combination...