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

Study of noise spectroscopy in (Bi, Pb)ィイD22ィエD2SrィイD22ィエD2CaCuィイD22ィエD2OィイD2yィエD2 intrinsic Josephson junctions

(Bi, Pb)D22D2SrD22D2CaCuD22D2OD2yD2 本征约瑟夫森结噪声光谱研究

基本信息

批准号：
10650054
负责人：
HAMASAKI Katsuyoshi
金额：
$ 2.05万
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：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

Mesa structure, which is produced from highly anisotropic BiィイD22ィエD2SrィイD22ィエD2CaCuィイD22ィエD2OィイD2xィエD2 (BSCCO) single crystal, shows the Josephson effect in c-direction. Many researchers have discussed the transport mechanism of this intrinsic Josephson junction and claimed that at low temperature the stack of SIS (Superconductor/Insulator/Superconductor) Josephson tunnel junctions is naturally formed along the c-axis in the mesa. One of the important and useful spectroscopic tools for a better understanding of the transport mechanism of high-Tc superconductors is low-frequency noise property. Han et al. have examined the 1/f noise power spectral density for BSCCO single crystals as a function of magnetic field, and temperature. They have widely discussed the physical origin of low frequency voltage noise phenomena in BSCCO single crystal near the superconducting transition point. For high-Tc BSCCO mesas, however, experimental study on the noise characteristics has not yet been reported.We have measured low frequency voltage noise properties across mesa stacks of intrinsic Josephson junctions in BiィイD22ィエD2SrィイD22ィエD2CaCuィイD22ィエD2OィイD2xィエD2 (BSCCO) single crystals as a function of bias voltage. The mesas were fabricated on the surface of cleaved BSCCO single crystals using standard photolithography and Ar ion-milling techniques. For the current-voltage (I-V) curve, increasing the bias current beyond the critical current IィイD2cィエD2 leads to several finite voltage jump. Ramping the bias current up and down repeatedly yields many discrete branches of the I-V characteristics. The IィイD2cィエD2 of the surface junction in the mesa approximately equals to those of inner junctions. The magnitude of the 1/f noise spectral density was found to increase monotonically with the branch number at fixed bias current. No anomalously enhanced l/f noise was observed.

由高度各向异性的BSCCO （BSCCO）单晶形成的台状结构在c方向上表现出约瑟夫森效应。许多研究者讨论了这种本征Josephson结的输运机制，并声称在低温下，SIS (Superconductor/Insulator/Superconductor) Josephson隧道结的堆叠沿着台面的c轴自然形成。为了更好地理解高温超导体的输运机制，其中一个重要而有用的光谱工具是低频噪声特性。Han等人研究了BSCCO单晶的1/f噪声功率谱密度作为磁场和温度的函数。他们广泛地讨论了超导过渡点附近BSCCO单晶中低频电压噪声现象的物理来源。然而，对于高tc BSCCO平台，对其噪声特性的实验研究尚未见报道。我们测量了BSCCO单晶中内禀约瑟夫逊结的台垒低频电压噪声特性，并将其作为偏置电压的函数。利用标准光刻技术和氩离子铣削技术在劈裂的BSCCO单晶表面制备了平台。电流电压(电流-电压曲线,增加了临界电流偏置电流超出我ィイD2cィエD2导致几个有限的电压跳。反复地将偏置电流上下倾斜会产生许多I-V特性的离散分支。台面表面结的I γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ γ。在固定偏置电流下，1/f噪声谱密度的大小随支路数的增加而单调增加。未观察到异常增强的l/f噪声。