权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Research on SIS nanoarray-type high-frequency mixer using Bi-2212 single crystals

Bi-2212单晶SIS纳米阵列型高频混频器的研究

基本信息

批准号：
15560040
负责人：
HAMASAKI Katsuyoshi
金额：
$ 2.37万
依托单位：
Nagaoka University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

High-quality Bi_2Sr_2CaCu_2O_<8+δ>(Bi-2212) single crystals were grown by a self-flux method without mixing and grinding of reagent starting powders. During the crystal growth process, a pressure (<0.4 N/cm^2) was applied using a brick placed on the cap on an alumina crucible. We obtained high-quality single crystals with zero-resistance transition temperature, T_<c,zero>【approximately equal】89K, with this techniques. We also developed new fabrication process of stacked intrinsic Josephson junctions using Bi-2212 crystals. For the planarization of the stacks, the crystal around the junction window was modified to insulating layer by dipping into the solution of hydrochloric acid. For the concentration is lower than 0.1%, the planarization of the stack was fully achieved. For the concentration is higher than 0.5%, however, the planarization was spoiled. The number of intrinsic junctions in the stack linearly increased with increasing the concentration in the range from 0.05 to 0.2%. The … More thickness of the acid-treated layer can be evaluated by the number of the branches in I-V curve. This well controlabillity of the number of the junctions in the planarized stacks is useful for the electronics applications, such as high-frequency mixer. The current-voltage (I-V) characteristics of the stacks were uniform and observed distinct resistive branches with large hysteresis even at 77K, which can be explained by a series connection of highly capacitive Josephson junctions. At higher temperatures than 40K, we found that the return current Ir of the intrinsic junction depended strongly on the temperature, T. We analyzed the Ir-T characteristics using simple resistively and capacitively shunted junction (RCSJ) model in view of the temperature dependence of the c-axis resistance of the stack. The Ir-T characteristics were found to be well explained by the Zappe theory based on the RCSJ model. The present results may be useful information for a better understanding of the Bi-2212 intrinsic Josephson characteristics. Less

采用自通量法制备了高质量的Bi_2Sr_2CaCu_2O_<8+δ>(Bi-2212)单晶，无需混合研磨。在晶体生长过程中，使用放置在氧化铝坩埚盖上的砖施加压力（<0.4 N/cm^2）。我们用该技术获得了零电阻转变温度T_<c，零>【约等于】89K的高质量单晶。我们还开发了利用Bi-2212晶体叠置本禀约瑟夫森结的新工艺。为了使叠层平面化，将结窗周围的晶体浸入盐酸溶液中修饰为绝缘层。当浓度低于0.1%时，叠层完全实现了平面化。当浓度大于0.5%时，表面的平面化被破坏。在0.05 ~ 0.2%的浓度范围内，随着浓度的增加，本征结的数量呈线性增加。酸处理层的厚度可以通过I-V曲线上分支的数量来判断。这种平面化堆叠中结数的良好可控性对高频混频器等电子应用非常有用。即使在77K时，堆叠的电流-电压（I-V）特性也是均匀的，并且观察到明显的电阻分支，并且具有较大的滞后，这可以通过高容性约瑟夫森结的串联来解释。在高于40K的温度下，我们发现本征结的返回电流Ir与温度t有很强的相关性，我们使用简单的电阻和电容分流结（RCSJ）模型分析了Ir- t特性，考虑到堆叠c轴电阻的温度依赖性。基于RCSJ模型的Zappe理论可以很好地解释Ir-T特征。本研究结果可能为更好地理解Bi-2212本征约瑟夫森特性提供有用的信息。少