Sanyo Electric Co., Ltd.

Ryokan Yuasa

Masaaki Nemoto

Shuji Fujiwara

Masao Nakao

Hiroaki Furukawa

Yorinobu Yoshisato

Isao Yoshida

Seiichi Tokunaga

Shuichi Yoshikawa

A precursor is made from a plurality of materials having different vapor pressures. The precursor and a source material are placed in a closed heat treatment furnace. The source material is materials which are the same as some of the materials contained in the precursor and having particular vapor pressures. The precursor and source material is thermally treated in the furnace while the source material is being supplied, so the particular materials in the precursor have their evaporation suppressed, thereby forming compounds. The compounds may be oxide superconductors, oxide dielectric, and so on.

Method for producing mixed metal oxide compounds

An oxide film having a desired pattern is first formed on a magnesia substrate. A superconducting oxide film is then formed on the exposed portion of the magnesia substrate and also on the oxide film. Thus, a tilt-boundary junction is formed in the boundary between the superconducting oxide film portion on the magnesia substrate and the superconducting oxide film portion on the oxide film. The tilt-boundary junction functions as a Josephson junction. By utilizing the Josephson junction in the tilt-boundary junction, a SQUID pattern can be formed on the magnesia substrate to provide a SQUID device.

Process of making squid device having tilt-boundary junction

An ion beam is irradiated to an oxide superconducting thin film formed on a substrate to disturb the crystal structure of the superconducting thin film and thus forming a damaged layer. The damaged layer has higher solubility in a halogen solution has a faster etching rate than other portions. Then, the superconducting thin film is etched by using a halogen solution to remove the damaged layer and form a groove at that portion. As a result, a groove of a desired form can be provided efficiently.

Method for processing superconducting thin films

A method of forming a fine groove on a superconducting thin film. A superconducting oxide thin film is formed on a MgO substrate, and a damaged layer is formed thereon by irradiating the superconducting thin film with focused ion beams to such a degree that not sputter is generated and the crystalline structure of the superconducting thin film is disturbed. The damaged layer is then removed by treatment with a strong alkali such as KOH. Thus, a fine groove is effectively formed. By inserting an oxide layer between the substrate and the superconducting thin film, a Josephson junction device suitable for superconducting transistors is produced.

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Tsukuba, Japan

Ryokan Yuasa