Experimental Evaluation of Self-Heating Effect in Intrinsic Josephson Junctions Using Pulse Current Measurements
Experimental Evaluation of Self-Heating Effect in Intrinsic Josephson Junctions Using Pulse Current Measurements
复制标题
使用脉冲电流测量对本征约瑟夫森结自热效应进行实验评估
DOI：
10.1109/tasc.2017.2669648
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发表时间：
2017
影响因子：
1.8
通讯作者：
Tsukamoto Takehiko
中科院分区：
文献类型：
--
作者：
Oikawa Dai;Tanaka Hiromi;Tsuzuki Keita;Andoh Hiroya;Sugiura Toko;Tsukamoto Takehiko
层状高临界温度超导体如单晶Bi2Sr2CaCu2O8+δ(Bi2212)中的本征约瑟夫森结(IJJ)由多个原子堆积的约瑟夫森结组成，其电流-电压(I-V)特性受自加热的影响。因此，评估IJJ的自热效应是很重要的。通常采用脉冲电流测量技术来减小自热效应。然而，在台面型IJJ样品中，自热不仅是由于在电压态IJJ中施加的电压，而且还由于电极与台面顶部之间的接触电阻。在以前的研究中已经发现，对于电极接触良好的小样本，台面顶部的电极可以帮助冷却台面。然而，在大样本中，由于接触电阻引起的加热效应还没有得到很好的研究。本文采用脉冲电流测量的方法，对台面型IJJ的I-V特性和自热特性进行了实验研究。此外，为了评估接触电阻对I-V特性的影响，我们提出了一种新的脉冲波形，因为当使用传统的脉冲测量时，准粒子分支的电压值比通过直流测量得到的电压值要大得多。我们使用该波形测量了I-V特性，以确定由于电极和台面顶部之间的接触电阻而产生的热的影响。我们发现，在这种情况下，电压受到了相当大的抑制。
Intrinsic Josephson junctions (IJJs) in layered high-critical-temperature superconductors such as single-crystal Bi2Sr2CaCu2O8+ δ(Bi-2212), which comprises several atomically stacked Josephson junctions, have been intensively studied, and it is known that the current-voltage (I-V ) characteristics of IJJs are affected by self-heating. Therefore, evaluating the self-heating effect in the IJJs is important. Pulse current measurement techniques are commonly employed to reduce the self-heating effect. However, in mesa-type IJJ samples, self-heating occurs not only owing to the applied voltage in voltage-state IJJs, but also owing to the contact resistance between the electrode and the top of the mesa. It has been found in previous studies, for small samples with good electrode contacts, that an electrode on the top of the mesa can help to cool the mesa. However, the effect of heating owing to the contact resistance has not been well studied in large samples. In this paper, the I-V and self-heating characteristics of mesa-type IJJs were experimentally investigated for devices wherein self-heating was suppressed using pulse current measurements. Furthermore, to evaluate the contact resistance effect on the I-V characteristics, we proposed a new pulse waveform, because when using the conventional pulse measurement, the voltage values of the quasiparticle branch were much larger than those obtained via the dc measurement. We measured the I-V characteristics using this waveform to determine the effect of heat generation that occurs due to the contact resistance between the electrode and the top of the mesa. We found that in this case, the voltage was considerably suppressed.