Sumitomo Electric Industries, Limited

The Tokyo Electric Power Company, Incorporated

Kabushiki Kaisha Toshiba

The Toyko Electric Power Company, Incorporated

Kiyoshi Okaniwa

Tsukushi Hara

Noriyuki Yoshida

Satoshi Takano

Takahiko Yamamoto

Shigeru Okuda

Noriki Hayashi

Daisuke Ito

Yoshihisa Masuda

Kazuyuki Tsurunaga

Mitsuhito Sawamura

In a method of preparing an oxide superconducting thin film having a composition of Y-Ba-Cu-O, for example, using laser ablation, which comprises the steps of applying a laser beam to a target containing components of an oxide superconductive material and depositing particles, being thereby scattered from the target, on a substrate, the oxygen gas flow rate during film deposition is set to be at least 50 SCCM, the oxygen gas pressure during film deposition is set to be 10 to 1000 mTorr, the distance between a target 9 and a substrate 10 is set to be 40 to 100 mm, the temperature of the substrate 10 is set to be 600.degree. to 800.degree. C., the energy density of a laser beam 7 on the surface of the target 9 is set to be at least 1 J/cm.sup.2, and the laser pulse energy is set to be at least 10 mJ.

In-situ laser ablation method for forming oxide superconducting films

In order to enable formation of a smooth and dense oxide superconducting film with no clear appearance of grain boundaries in a fine structure even at a high film forming rate, a laser ablation method is employed to apply a laser beam 2 to a target 1 containing components of an oxide superconductive material and deposit particles, which are thus scattered from the target 1, on a substrate 3, while gaseous oxygen is supplied from a gaseous oxygen inlet 7 toward laser plasma 6, which is generated by the application of the laser beam 2.

Method of and apparatus for preparing oxide superconducting film

In order to enable formation of a smooth and dense oxide superconducting film with no clear appearance of grain boundaries in a fine structure even at a high film forming rate, a laser ablation method is employed to apply a laser beam 2 to a target 1 containing components of an oxide superconductive material and deposit particles, which are thus scattered from the target 1, on a substrate 3, while gaseous oxygen is supplied from a gaseous oxygen inlet 7 toward laser plume 6, which is generated by the application of the laser beam 2, and to a portion of the target irradiated with said laser.

Method of preparing oxide superconducting films by laser ablation

In order to prepare an elongated oxide superconducting material which exhibits a high critical current density, a tape-type substrate (7) of silver, for example, formed by unidirectional solidification is prepared and an excimer laser beam (9) is applied to target (8) of an oxide superconductor to deposit atoms and/or molecules being scattered from the target (8) on the substrate (7), thereby forming an oxide superconducting film on the substrate (7).

Laser ablation method of preparing oxide superconducting films on

In a superconducting AC (alternating current) current limiter, quenched trigger coil assembly is quickly recovered to the superconductive state by minimizing a loop current flowing through the trigger coil assembly. The superconducting AC current limiter comprises: a cylindrical core; a superconducting current limiting coil wound on the core, and inserted into an AC power transmission line, for limiting an overcurrent flowing through the AC power transmission line when a failure happens to occur therein; a superconducting trigger coil assembly coaxially wound inside the superconducting current limiting coil on the core, and magnetically coupled to the current limiting coil, for triggering current limiting operation by the current limiting coil when most of the overcurrent flows through the trigger coil assembly, the superconducting trigger coil assembly being arranged by first, second, third and fourth trigger coils in such a manner that the first trigger coil is series-connected to the fourth trigger coil thereby to constitute a first series trigger coil circuit, the second trigger coil is series-connected to the third trigger coil thereby to constitute a second series trigger coil circuit, the first and second series trigger coil circuits are connected in parallel with each other, one end of which is connected to one end of the superconducting current limiting coil and the other end of which is connected via a quenching switch to the other end of the current.

Superconducting AC current limiter equipped with quick-recoverable

An oxide superconducting thin film formed by laser ablation comprises a matrix formed of c-axis oriented superconducting phases and foreign phases which are different in crystal orientation from the matrix. In order to improve critical current density of the oxide superconducting thin film, preferably selected are such conditions that the size of each superconducting phase in its a-b plane is not more than 0.1 .mu.m in diameter, the size of each superconducting phase along its c-axis direction is equal to the thickness of the oxide superconducting thin film, the foreign phases at least partially pass through the oxide superconducting thin film along the direction of thickness, the size of each foreign phase is at least 0.01 .mu.m and not more than 5 .mu.m in diameter, each foreign phase has an a-axis or a c-axis perpendicularly oriented with respect to the major surface of the oxide superconducting thin film, and the like.

Growing community of inventors

Chofu, Japan

Kiyoshi Okaniwa