Combined breakdown of a dielectric nanolayer to form a Josephson bridge A.V. Krevsun S.I. Bondarenko V.P. Koverya B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of

2025-04-27 0 0 271.56KB 10 页 10玖币

侵权投诉

Combined breakdown of a dielectric nanolayer to form a Josephson bridge

A.V. Krevsun, S.I. Bondarenko, V.P. Koverya

B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of

Sciences of Ukraine, Kharkiv 61103, Ukraine

E-mail: bondarenko@ilt.kharkov.ua

Electrical breakdown of a dielectric nanolayer between film electrodes under the combined

action of direct current and capacitor discharge current makes it possible to form Josephson bridges

with a reproducible resistance exceeding 1 Ω. A new feature of the formation of a bridge during

electrical breakdown, which is preceded by a series of preliminary breakdowns (auto breakdowns) of a

dielectric nanolayer, has been discovered. The mechanism of the process and the role of the thickness

of the cathode film in the formation of the bridge are discussed.

Keywords: electrical breakdown, Josephson bridge, dielectric nanolayer.

1. Introduction

It is known [1-7] that as a result of electrical breakdown of a thin dielectric layer between two metal

electrodes, a conducting channel is formed in it in the form of a metal bridge. Almost all numerous

studies of the formation of such bridges were previously carried out using non-superconducting

massive electrodes. For the first time, studies of some properties of bridges made of superconducting

materials formed as a result of electrical breakdown were carried out in 1970-1976 in B.I. Verkin

Institute for Low temperature Physics and Engineering (ILTPE) [8, 9, 10]. At the same time, the use of

film electrodes was also new. The purpose of these studies was to elucidate the possibility of using

electrical breakdown to create a superconducting weak link between films with Josephson properties.

In particular, three methods were tested to achieve the breakdown of a dielectric: a smooth increase in

the electric voltage across it from a direct voltage source, a discharge of an electric capacitor through

it, and a single rectangular voltage pulse [10]. The material of the bridges formed by the electrical

breakdown was lead or a lead-tin compound, from which a thin cathode film was made. The features

of the cathode metal film transfer through the dielectric during breakdown are an important and little

studied issue. The result of the initial studies of the formation of superconducting bridges during the

electrical breakdown of a dielectric was an experimental proof of the fundamental possibility of

creating such Josephson weak links [9, 10]. In the future, based on these film bridges, it was planned to

develop miniature film superconducting direct current (DC) quantum interferometer with high

sensitivity and stability of parameters even under significant external mechanical influences.

At the same time, a number of questions concerning the patterns of bridge formation remained

unexplained. The answer to some of them was obtained by us in a recent work [11], in which an

electrical breakdown of the dielectric oxide layer of a niobium film with a thickness of 30 nm was

carried out using a 50% indium–50% tin alloy film with a thickness of 100 nm as a cathode. In

particular, for the first time it was found that with a smooth (less than 1 V/s) increase in voltage up to

breakdown, the minimal and reproducible total value of the bridge resistance (RΣ  3 Ω), consisting of

the intrinsic resistance of the bridge Rb and the resistance of the contact conductor, was achieved at a

breakdown current of 10 mA. In this case, the indicated resistance values at a temperature of T=300K

were reproducible on dozens of bridges. The diameter (about 25 nm) of the bridge itself with a

resistance of Rb 1 Ω was determined by calculation. It was experimentally proved that the bridge

material is identical to the indium-tin alloy of a cathode film. At the same time, the manufacture of

Josephson bridges (JB) by the electrical breakdown method is much simpler than by known traditional

methods.

It was also shown that in the temperature range of 300-77K, the dependence of the resistance of

the cathode film and bridges on temperature with its decrease is linearly decreasing, and their

temperature coefficients of resistance (TCR) are within (2.0 ± 0.3)×10 -3 K-1. Note that the TCR of

massive indium and tin are (4.9 and 4.4) × 10-3 K-1, respectively.

The importance of determining the resistance value of the bridge at T=300K is that it correlates

with the value of its normal resistance (NR) near the superconducting transition and the critical current

of the JB in the superconducting state, which determines its Josephson properties [12].

At present, there are a number of unresolved issues in the technology of manufacturing JB

using breakdown. These include questions about the possibility to form a reproducible JB with Rb ˃ 1

Ohm, about influence of the thickness of the cathode film on the formation of JB, as well as the use of

alternative methods of electrical breakdown of the dielectric and their influence on the NR value of the

resulting JB. In particular, such a method can be the breakdown of niobium oxide using the combined

electrical action on the oxide of direct current and the current of a capacitor connected in parallel and

charged to the breakdown voltage.

The purpose of this work was to find answers to these questions through experimental studies.

2. Setting up the experiment.

Figure 1 shows the electrical circuit of the device for the combined breakdown of niobium oxide in

order to form JB.

文档加载中……请稍候！
如果长时间未打开，您也可以点击刷新试试。

下载文档到电脑，查找使用更方便

10 玖币 0人已下载

立即下载

摘要：

CombinedbreakdownofadielectricnanolayertoformaJosephsonbridgeA.V.Krevsun,S.I.Bondarenko,V.P.KoveryaB.VerkinInstituteforLowTemperaturePhysicsandEngineeringoftheNationalAcademyofSciencesofUkraine,Kharkiv61103,UkraineE-mail:bondarenko@ilt.kharkov.uaElectricalbreakdownofadielectricnanolayerbetweenfilmel...

展开>> 收起<<

Combined breakdown of a dielectric nanolayer to form a Josephson bridge A.V. Krevsun S.I. Bondarenko V.P. Koverya B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of.pdf

共10页,预览2页

还剩页未读，继续阅读

声明：本站为文档C2C交易模式，即用户上传的文档直接被用户下载，本站只是中间服务平台，本站所有文档下载所得的收益归上传人(含作者)所有。玖贝云文库仅提供信息存储空间，仅对用户上传内容的表现方式做保护处理，对上载内容本身不做任何修改或编辑。若文档所含内容侵犯了您的版权或隐私，请立即通知玖贝云文库，我们立即给予删除！

Combined breakdown of a dielectric nanolayer to form a Josephson bridge A.V. Krevsun S.I. Bondarenko V.P. Koverya B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of

相关推荐

开通VIP享超值会员特权

作者详情

相关内容

热门标签

举报选择: