THE MEISSNER EFFECT IN TaSe_3

TaSe_3 中的迈斯纳效应

• 批准号: 62540222
• 负责人: NAGATA Shoichi
• 金额: $ 1.41万
• 依托单位: Muroran Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1987
• 资助国家: 日本
• 起止时间: 1987 至 1989
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-62540222/
• 关键词: TaSe_3; Superconductivity; Quasi-one-dimensional Conductor; The Meissner Effect; SQUID; Diamagnetism; London Model; ヘリウム3クライオスタット; ヘリウム-3クライオスタット; 一次元伝導体; マイスナー効果; 臨界電流密度; ロンドン方程式; 超伝導量子干渉計; 常伝導状態; 低次元伝導体; 一次元伝導; ウムクラップ散乱; 臨界電流; 臨界磁場

THE MEISSNER EFFECT IN TaSe_3 The Meissner effect of the quasi-one-dimensional conductor TaSe_3 is studied using a SQUID magnetometer. Susceptibility x does not show any significant variation of diamagnetism, with magnetic fields parallel and perpendicular to crystalline b-axis over a low magnetic field range of 7.2 mOe to 4.0 Oe. The diamagnetism is quite weak and the value of chi is much less than -3.OX10^<-3> emu/cm^3. Furthermore, thd susceptibility chi does not exhibit any indication of an abrupt change at 2.1 K. A single whisker consists of many fibers where some fibers (very thin filament-like) become superconducting below 2.1 K.Resistivity of TaSe_3 drops near zero below 2.1 K. Why is the Meissner effect suppressed quite strongly in TaSe_3 ? A basic origin of this small diamagnetism is discussed on the basis of numerical computer calculations for the London model.As a simplified model, the diamagnetic susceptibility chi for a infinite cylinder having radius, a , is calculated systematically as a function of a/lambda, here lambda is the London penetration depth. In TaSe_3, the superconducting region is strictly restricted to extremely thin filaments along the b-axis in the single whisker. Furthermore. these superconducting filaments are individually isolated above 0.40 K in the whisker. The radii of the filaments are much less than lambda ( at most a/lambda <less than or equal>0.30 ), then, the magnetic flux will penetrate uniformly.Consequently the Meissner effect is substantially smeared out.It should be noted that our experimental results give the single whisker's intrinsic material property. Our results could totally differ from that of the large amount of massive specimens which are randomly oriented and are greatly interpenetrating.

用SQUID磁力计研究了准一维导体TaSe_3的迈斯纳效应。在7.2 mOe到4.0 Oe的低磁场范围内，磁化率x没有显示出任何显著的抗磁性变化，磁场平行和垂直于晶体b轴。抗磁性很弱，chi值远小于-3。OX10 ^ < 3 > emu /厘米^ 3。此外，敏感性chi在2.1 K时没有表现出任何突变迹象。单个晶须由许多纤维组成，其中一些纤维（非常细的长丝状）在2.1 K以下变得超导。在2.1 K以下，TaSe_3的电阻率降至接近零。为什么迈斯纳效应在TaSe_3中被强烈抑制？本文在对伦敦模型进行数值计算的基础上，讨论了这种小抗磁性的基本来源。作为一个简化模型，我们系统地计算了半径为a的无限圆柱体的抗磁化率chi作为a/lambda的函数，其中lambda为伦敦穿透深度。在TaSe_3中，超导区域被严格限制在单晶须沿b轴的极薄细丝上。此外。这些超导细丝被单独隔离在0.40 K以上的晶须中。细丝的半径远小于λ（最多a/ λ <小于等于>.30），磁通量均匀穿透。因此，迈斯纳效应基本上被抹去了。值得注意的是，我们的实验结果给出了单晶须的固有材料性质。我们的结果可能与大量随机取向、互穿性强的块状标本的结果完全不同。

项目成果

S.Nagata and I.Shirotani: "Normal-State-Electrical Resistivity of TaSe_3" Jpn.J.Appl.Phys.Series1. 1. 153-154 (1988)

S.Nagata 和 I.Shirotani：“TaSe_3 的正常状态电阻率”Jpn.J.Appl.Phys.Series1。

S.Nagata,Y.Hodolsawa,S.Taniguchi and K.Yamaya: "Normal-State Electrical Resistivity in Quasi-one-dimensional Conductor TaSe_3" J.Phys.Soc.Jpn.56. 2225-2226 (1987)

S.Nagata、Y.Hodolsawa、S.Taniguchi 和 K.Yamaya：“准一维导体 TaSe_3 中的常态电阻率”J.Phys.Soc.Jpn.56。

Shoichi NAGATA: "The Meissner Effect in TaSe_3" Proc. Int. Conf. on Low Temperature Phys (LT-19) 1990.

Shoichi NAGATA：“TaSe_3 中的迈斯纳效应”Proc。

S.Nagata,T.Aochi,S.Ebisu and S.Chikazawa: "Characteristics in an rf Superconducting QuantumInterference Device as a Function of Applied Magnetic Flux: Systematic Calculations" Phys.Rev B. (1990)

S.Nagata、T.Aochi、S.Ebisu 和 S.Chikazawa：“作为应用磁通量函数的射频超导量子干涉装置的特性：系统计算”Phys.Rev B. (1990)

Shoichi,NAGATA: J.Phys.Soc.Jpn.56. 2225-2226 (1987)

永田翔一：J.Phys.Soc.Jpn.56。