Development of High Tc SQUID Magnetometer

高温SQUID磁力计的研制

• 批准号: 06650472
• 负责人: ENPUKU Keiji
• 金额: $ 1.34万
• 依托单位: KYUSHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06650472/
• 关键词: High Tc superconductor; SQUID magnetometer; Josephson junction; Grain-bounday junction; Magnetic coupling; l; f noise; 熱雑音

In this project, we have developed superconducting quantum interference device (SQUID) using high Tc superconductors. In order tomake dc SQUID,high quality YBaCuO superconducting thin films are deposited on SrTiO3 bicrystal substrate with laser ablation method. The so-called bicrystal junction fabricated in this way shows characteristics expected from RSJ model, and enables stable SQUID operation at T=77K.For the improvement of the SQUID characteristics, we have investigated quantitatively the effect of large thermal noise at T=77K on the characteristics. It is shown that the value of inductance available at T=77K is limited below L<150pH due to large thermal noise. It is important to take into account this limitation for the design of the SQUID.Moreover, we have studied dependencies of the SQUID characteristics on SQUID parameters. From theoretical and experimental studies, we show the design rule for the development of high performance SQUID.This design rule has been used in many laboratories.In order to realize SQUID magnetometer, we have also studied the so-called magnetic coupling circuit. It is important to realeze both high performance SQUID and efficient coupling circuit. We should use inductance ranging from 50pH to 150 pH in order to satisfy these requirement. The magnetometer designed in this way shows good performance at T=77K

在本计画中，我们利用高温超导体研制出超导量子干涉器。为了制作dc SQUID，用激光烧蚀法在SrTiO_3双晶衬底上沉积了高质量的YBaCuO超导薄膜。用这种方法制备的双晶结具有RSJ模型所期望的特性，使SQUID能在T= 77K下稳定工作。为了改善SQUID的特性，我们定量地研究了T=77K下大的热噪声对SQUID特性的影响。结果表明，由于热噪声较大，T=77K时的电感值限制在L<150pH以下。在SQUID的设计中考虑到这一限制是很重要的。此外，我们还研究了SQUID特性对SQUID参数的依赖关系。本文从理论和实验两方面研究了研制高性能SQUID的设计原则，该原则已在许多实验室得到应用。为了实现SQUID磁强计，我们还研究了所谓的磁耦合电路。实现高性能的SQUID和高效的耦合电路具有重要意义。为了满足这些要求，我们应该使用从50 pH到150 pH的电感。用这种方法设计的磁强计在T=77K时表现出良好的性能

项目成果

K.Enpuku: "Parameter dependent characteristics of a high Tc dc SQUID" Journal of Applied Physics. 78. 3498-3503 (1995)

K.Enpuku：“高 Tc dc SQUID 的参数相关特性”应用物理学杂志。

K. Enpuku: "Modulation voltage of high Tcdc superconducting quantum interference device with damping resistance" Japanese Journal of Applied Physics. 33. L722-L725 (1994)

K. Enpuku：“具有阻尼电阻的高Tcdc超导量子干涉装置的调制电压”日本应用物理学杂志。

K. Yoshida: "Evaluation of wagnetic penetration depth and surface resistallce of superconducting thin flms using coplanar wave guides" IEEE TrausacTions on Applied Superconductivity. 5. 1979-1982 (1995)

K. Yoshida：“使用共面波导评估超导薄膜的磁穿透深度和表面电阻”IEEE TrausacTions on Applied Superconductivity。

K.Enpuku et al.: "Modulation voltage of high Tc dc superconducting quantum interference device with damping resistance." Jpn.J.Appl.Phys.vol.33. L722-L725 (1994)

K.Enpuku等人：“具有阻尼电阻的高Tc直流超导量子干涉装置的调制电压”。

Keiji Enpuku: "Modulation voltage of high Tc dc SQUID with damping resistance" Japanece Journal of Applied Physics. 33. L722-L725 (1994)

Keiji Enpuku：“具有阻尼电阻的高 Tc dc SQUID 的调制电压”Japanece 应用物理杂志。