Intrinsic noise temperatures of YBa2Cu3O7−δ Josephson devices on bicrystal substrates and the upper frequency limit for their operation
Intrinsic noise temperatures of YBa2Cu3O7−δ Josephson devices on bicrystal substrates and the upper frequency limit for their operation
复制标题
双晶衬底上 YBa2Cu3O7−δ 约瑟夫森器件的固有噪声温度及其工作频率上限
DOI：
10.1063/1.363672
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发表时间：
1996
影响因子：
3.2
通讯作者：
Peiheng Wu
中科院分区：
文献类型：
--
作者：
J. Chen;H. Myoren;K. Nakajima;T. Yamashita;Peiheng Wu
Following a method proposed by Divin and Modovets [Sov. Tech. Phys. Lett. 9, 108 (1983)], we have measured at millimeter waveband the intrinsic noise temperatures TN of YBa2Cu3O7−δ Josephson junctions or dc superconducting quantum interference devices (SQUIDs) fabricated on SrTiO3, yttria‐stabilized ZrO2, or Si bicrystal substrates. Over wide ranges of physical temperatures TP and the junction’s normal resistance RN, it was found that TN follows TP pretty well. This indicates that the intrinsic noise in the devices is dominated by Johnson noise. TN was also measured in cases where there is external magnetic field applied, or where there is another microwave radiation like the local oscillator in a mixer. The magnetic field or microwave radiation does not seem to affect TN in any appreciable way. To estimate the high frequency performance of the junctions on Si bicrystal substrates, direct irradiation by a far infrared laser at 1.81 THz is carried out and the clear first Shapiro step is observed.
