| 摘要 |
PURPOSE:To obtain a tunnel barrier, wherein both a large current density and excellent covering property can be obtained compatibly by forming the barrier of the double-layered structure of MgO and CeO2. CONSTITUTION:A first barrier layer 2 and a second barrier layer 3, which are formed between a high dielectric 1 and an oxide superconductor 4, are both deposited by using a laser migration method. At this time, e.g. MgO is used for the first barrier 2, and CeO2 is used for the second barrier layer 3. Thus, two kinds of materials selected from among CeO2 and NdGaO3, wherein MgO, CeO2 and Ca are doped, are combined, and the tunnel barrier having the double-layered structure is formed. Therefore, the large current density and the excellent covering property, which are difficut to be obtained with a single-layer barrier, can be made compatible.
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