中文摘要：

超导约瑟夫森结是超导量子比特的核心元件,由约瑟夫森结组成的直流超导量子干涉器（DC-SQUID）由于其具有较高的探磁灵敏度,在超导磁通量子比特量子位测量中具有重要的作用.我们用铝为超导材料,采用电子束斜蒸发及静态氧化的方法制备了由两个Al/Al2O3/Al隧道结并联组成的DC-SQUID样品.将DC-SQUID样品置于20-1000mK范围内的不同温度下,对其跳变电流分布进行了测量.在50mK明显观测到了隧道结跳变电流机制由宏观量子隧穿到热激发的转变,并且在高于80mK时,观测到了相位扩散的现象.这对于隧道结相位动力学研究具有重要意义.

英文摘要：

Josephson junction is the key element of the superconducting quantum bits. DC superconducting quan- tum interference device （DC-SQUID） plays a important role in the measurement of superconducting flux quantum bit because of its high sensitivity in magnetic field probe. By evaporating aluminum from slanted angles and the method of static oxidization, we fabricated the DC-SQUID sample composed by two parallel tunnel junctions Al/Al2O3/AI. Placing the sample in different temperature between 20inK and 1000mK, we had the measurement of switching current distribution（SCD）. The transition from macroscopic quantum tunneling mechanism（MQT） to thermal activation（TA） is clearly observed in 50inK. When the temperature is higher than 80inK, the phase diffusion phenomenon （PD） is observed. It is of great importance for the research of phase dynamics of tunnel junction.