Japan Science and Technology Corporation

Japan Science and Technology Agency

Tsutomu Yamashita

Sang-Jae Kim

Hiroshi Maeda

Mitsunori Sato

Sangjae Kim

Masanori Nagao

The present invention relates to a defect-free oxide high-critical temperature superconductor acicular crystal, that is, an oxide high-critical temperature superconductor acicular crystal that is substantially a perfect crystal and also relates to a method for producing the same, wherein such a crystal is essential for achieving superconducting electronic devices. The oxide high-critical temperature superconductor acicular crystal of the present invention includes an acicular crystal having a BiSrCaCuO(Bi-2223) crystal structure and is grown from a powder compact by heat-treating the powder compact in an oxygen atmosphere, wherein the powder compact contains an oxide having the Bi-2223 crystal structure and TeO, CaO, or (SrCa)TeO. The achievement of the acicular crystal having the Bi-2223 crystal structure contributes to the development of superconducting electronic devices that have been theoretically proposed but have not been achieved.

Oxide high-critical temperature superconductor acicular crystal and its production method

A three-dimensional element is fabricated from a high-temperature superconductor. The method and apparatus can fabricate, for example, a single-electron tunnel device or an intrinsic Josephson device which utilize the layer structure peculiar to the high-temperature superconductor, with machining from the side surface of a monocrystal or thin film. In the focused-ion beam etching, a substrate holder which is rotatable about 360&deg;, is rotated, at the minimum, through an angle of about 90&deg;, and the thin film or monocrystal on the substrate is etched from the side surface thereof so as to fabricate the element. After the thin film or monocrystal is machined from above by means of an focused-ion beam to thereby form a bridge having a junction length, the sample is rotated by about 90&deg; (270&deg;). Subsequently, a multi-layer current path layer is formed through side-surface machining. The junction length is accurately controlled through measurement of the current path length from an image display.

Method and apparatus for fabricating three dimensional element from anisotropic material

A single electron tunneling transistor which has a multi-layer structure exhibiting a single electron tunneling effect even with processing accuracy of not greater than 0.1 &mgr;m. The multi-layer structure of the single electron tunneling transistor is characterized by alternately growing an electrically conductive layer and a tunneling barrier layer. The number of layers is 50 or more. The structure has a minute tunneling junction having an area on the order of 1 &mgr;m square.

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Miyagi, Japan

Tsutomu Yamashita