鉄アルセニド超伝導体における異なるネマティック感受性
Jiun-Haw Chu1, Hsueh-Hui Kuo, James G Analytis
1Department of Applied Physics and Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA. jhchu@berkeley.edu
Science (New York, N.Y.)
|August 11, 2012
まとめ
研究者らは,ネマティック感受性測定を用いた鉄プニクチド超伝導体における電子ネマティック相変化を特定した. この方法は,それを鉄弾性歪みと区別し,最適な超伝導性に近い量子相移行を指しています.
科学分野:
- 凝縮物質物理学 凝縮物質物理学
- マテリアルサイエンス 材料科学
背景:
- ランダウ理論における連続相変遷は,対称性の破裂によって特徴付けられています.
- 順序パラメータ間のカップリングは,相変遷の原動力を覆い隠す可能性があります.
- 鉄のピニクチド超伝導体は,複雑な相行動を示す.
研究 の 目的:
- 超伝導体における電子ネマティック・フェーズ・トランジションと鉄弾性歪曲を区別する.
- Ba{\Fe}{\1-x}Co{\x}{\2}As{\2}の相変化の性質を調査する.
- 潜在的な電子ネマティック量子相移行を特定する.
主な方法:
- ネマティック感受性の測定. ネマティック感受性の測定.
- Ba(Fe(1-x) Co(x))(2) As(2) 超伝導体特性についての分析.
- ランドー・パラダイム・アプリケーション.
主要な成果:
- ネマティック感受性測定は,電子ネマティック性をフェロ弾性から区別することに成功しました.
- 電子ネマティック・フェーズ・トランジションは,Ba (((Fe (((1-x) Co (((x)) (((2) As (((2)) で特定されました.
- 最適な超伝導温度に近い電子ネマティック量子相移行の証拠が見つかりました.
結論:
- ネマティック感受性は,超伝導体における複雑な相変遷を理解するための重要なツールである.
- この研究では,鉄のプニクチドに独特の電子ネマティック相があることが明らかになった.
- 電子ネマティック性に関連した量子臨界点は,超伝導性に関連している可能性があります.
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...
01:31Ferromagnetism
Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...
01:31Magnetic Susceptibility and Permeability
In linear magnetic materials, like paramagnets and diamagnets, magnetization is proportional to the magnetic field intensity. The constant of proportionality, a dimensionless number, is called magnetic susceptibility. The value of the susceptibility depends on the type of material.
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...
When diamagnetic materials are placed under an external magnetic field, the moments opposite to the field are induced. Hence, the susceptibility for diamagnets has a minimal negative value of 10-5–10-6. Since...
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...
01:26Diamagnetism
Materials consisting of paired electrons have zero net magnetic moments. However, when these materials are placed under an external magnetic field, the moments opposite to the field are induced. Such materials are called diamagnets. Diamagnetism is the response of the diamagnets when placed in an external magnetic field.
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets.
Diamagnetism was discovered by Anton Brugmans in 1778 when he observed that bismuth gets repelled by magnetic fields, thus theorizing that diamagnets get repelled by magnets.
01:28Magnetostatic Boundary Conditions
An electric field suffers a discontinuity at a surface charge. Similarly, a magnetic field is discontinuous at a surface current. The perpendicular component of a magnetic field is continuous across the interface of two magnetic mediums. In contrast, its parallel component, perpendicular to the current, is discontinuous by the amount equal to the product of the vacuum permeability and the surface current. Like the scalar potential in electrostatics, the vector potential is also continuous...