| 摘要 |
PURPOSE:To easily form a laminated tunnel junction by a method wherein a substrate whose number of pages can be confirmed and which is provided with an angular interval is used as a substrate on which an oxide superconductor film is formed because a lattice correction different from the lattice constant of its a-b plane is required. CONSTITUTION:Three targets (Bi2Sr2Ca2Cu4.5Ox, Br2Sr3Ca3Cu3Ox and Bi3Sr2Ca2Cu3Ox) whose composition is different are used, and a BiSrCaCuO superconducting film 2 is formed by a sputtering method. An SrTiO3 (110)1 whose number of pages can be confirmed and which is provided with an angular interval is used as a substrate because a lattice correction different from the lattice constant of the a-b plane of BiSrCaCuO is required. When an SrTiO3 insulating layer is selected as a laminated tunnel junction, a lattice interval is matched and it is epitaxially grown satisfactorily. The axis (a) or (b) of the conductor 2 is at 5.4Angstrom , and the SrTiO3 3 is of a cubic system one side of which is at 3.9Angstrom . The length of a diagonal line of the a-b plane of the conductor is at 7.6Angstrom and coincides approximately with 3.9Angstrom X2=7.8Angstrom . A growth operation is executed so as to match this value. When four corners of the a-b plane are to coincide with lattice points of the substrate, the axis (c) must be tilted as shown in the figure. Two or three crystal structures whose length of the axis (c) is different exist at the conductor film 2. Out of them, the axis (c) at 37Angstrom has a highest transition temperature.
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