High frequency operation of Josephson vortex flow transistor with a controlled damping
High frequency operation of Josephson vortex flow transistor with a controlled damping
复制标题
具有受控阻尼的约瑟夫森涡流晶体管的高频操作
DOI：
10.1109/77.621721
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发表时间：
1997
影响因子：
1.8
通讯作者：
R. Chicault
中科院分区：
文献类型：
--
作者：
J. Villégier;S. Nicoletti;M. Cyrille;R. Chicault
在非对称偏置约瑟夫森涡流晶体管(JVFT)中应用了高温超导结和LTS结，YBaCuO晶界结和Nb/AlOx-Al/Nb“SNOP”隧道结被用于非对称偏置约瑟夫森涡流晶体管。如格罗斯等人之前所示。(1995)，我们证明了在大屏蔽参数的JVFT中，电流偏置引起的自场效应可以用来提高电流增益。用实用的YBaCuO器件获得了约10~77K的增益。利用控制输入门与涡流SQUID阵列共面耦合，实验验证了器件的高频工作频率达到MHz，并外推到GHz，同时观察到了合理的跨阻值、带宽和动态范围。通过改变Nb隧道结的亚隙电阻，实验研究了阻尼值对JVFT性能的影响。在核磁共振、电磁兼容性或红外成像应用方面，由非对称高温超导JVFT制成的放大器可能与SQUID或FET放大器竞争。
Both HTS and LTS junctions, respectively YBaCuO grain boundary junctions made on MgO 24/spl deg/ [001] tilted bicrystals and shunted Nb/AlOx-Al/Nb "SNOP" tunnel junctions deposited on sapphire have been used in asymmetrically biased Josephson vortex flow transistors (JVFT). As shown previously by Gross et al. (1995), we verify that the self field effect induced by current bias in asymmetrically designed JVFT with large screening parameter /spl beta//sub L/ can be used for increasing the current gain. Gain of about 10 up to 77 K are obtained with practical YBaCuO devices. High frequency operation of the devices has been experimentally verified up to the MHz range and extrapolated to GHz by using the control input gate coupled in a coplanar configuration to the vortex flow SQUID array, while reasonable values of transresistance, bandwidth and dynamical range are observed. Influence of the damping on the JVFT performances has been also studies experimentally by varying the subgap resistance of the Nb tunnel junctions. Amplifiers made of asymmetrical HTS JVFT may be competitive with SQUID or FET amplifiers for NMR, Electromagnetic Compatibility or Infrared imaging applications.