SrCuO2-BaCuO2スーパーラットにおける超伝導性:人工的に層を重ねた超伝導材料の形成
Science (New York, N.Y.)
|September 30, 1994
まとめ
研究者らは,パルスレーザー沈着を用いた新しい人工超伝導体を合成した. これらの新しい材料は,無限層構造で安定し,高温超伝導性を70ケルビンまで発揮します.
科学分野:
- 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
- 固体化学 固体化学
背景:
- 高温超伝導は依然として重要な研究分野である.
- 人工的な層構造は,新しい超伝導特性への経路を提供します.
研究 の 目的:
- パルスレーザー沈殿法を使用して,新しい高温超伝導体を合成する.
- SrCuO(2) - BaCuO(2) を無限層構造内の超格子で安定させるため.
主な方法:
- パルスレーザーデポジション (PLD) 技術.
- 超網を安定させるためのエピタキシアル成長.
- 合成された薄膜化合物の特徴.
主要な成果:
- 人工的に層を重ねた化合物の合成が成功しました.
- 無限層構造における SrCuO(2) - BaCuO(2) スーパーグリットの安定化.
- 2つの新しい構造ファミリーの発見: Ba(2) Srn-1,Cun+1 O2n+2+デルタと Ba(4) Srn-1 Cun+3O2n+6+デルタ.
- 70ケルビンまでの温度で超伝導性を達成しました.
結論:
- パルスレーザーの堆積は,高度な超伝導材料の作成に有効です.
- 無限層構造は,新しい超伝導体ファミリーを宿すことができる.
- 合成された化合物は,高温超伝導性研究における重要な進歩を表しています.
関連する概念動画
01:28Types Of Superconductors
A superconductor is a substance that offers zero resistance to the electric current when it drops below a critical temperature. Zero resistance is not the only interesting phenomenon as materials reach their transition temperatures. A second effect is the exclusion of magnetic fields. This is known as the Meissner effect. A light, permanent magnet placed over a superconducting sample will levitate in a stable position above the superconductor. High-speed trains that levitate on strong...
01:24Superconductor
A substance that reaches superconductivity, a state in which magnetic fields cannot penetrate, and there is no electrical resistance, is referred to as a superconductor. In 1911, Heike Kamerlingh Onnes of Leiden University, a Dutch physicist, observed a relation between the temperature and the resistance of the element mercury. The mercury sample was then cooled in liquid helium to study the linear dependence of resistance on temperature. It was observed that, as the temperature decreased, the...
02:37Metallic Solids
Metallic solids such as crystals of copper, aluminum, and iron are formed by metal atoms. The structure of metallic crystals is often described as a uniform distribution of atomic nuclei within a “sea” of delocalized electrons. The atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties.
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...
01:17Theory of Metallic Conduction
The conduction of free electrons inside a conductor is best described by quantum mechanics. However, a classical model makes predictions close to the results of quantum mechanics. It is called the theory of metallic conduction.
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
02:33Lattice Centering and Coordination Number
The structure of a crystalline solid, whether a metal or not, is best described by considering its simplest repeating unit, which is referred to as its unit cell. The unit cell consists of lattice points that represent the locations of atoms or ions. The entire structure then consists of this unit cell repeating in three dimensions. The three different types of unit cells present in the cubic lattice are illustrated in Figure 1.
Types of Unit Cells
Imagine taking a large number of identical...
Types of Unit Cells
Imagine taking a large number of identical...
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...