A thin film of oxide superconductor possessing locally different crystal orientations and a processes for preparing the same

Claim 2

The thin film of oxide superconductor comprising first portions (11, 12) which are deposited on first buffer layer portions (31, 32) made of a material having such a crystal structure that a thin film of oxide superconductor whose c-axis is oriented along a direction which is perpendicular to said substrate (2) is easily brown, and second portions (10) which are deposited on second buffer layer portions (4) made of a material having such a crystal structure that a thin film of oxide superconductor whose c-axis is oriented along a direction which is in parallel to said substrate is easily grown.

Claim 3

The thin film set forth in claim 2, wherein said first portions (11, 12) consist of c-axis oriented thin films, while said second portions (10) consist of a-axis oriented thin films.

Claim 4

The thin film set forth in claim 2 or 3, wherein said first buffer layer portions (31, 32) are made of LaAlPO₃ or PrGaO₃ and said second buffer layer portions (4) are made of Al₂O₃ or MgO.

Claim 5

The thin film set forth in any one of claim 2 to 4, wherein said buffer layer portions (31, 32, 4) have a thickness of about 200 nm.

Claim 6

The thin film set forth in any one of claim 2 to 5, wherein said substrate (2) is MgO (100), SrTiO₃, CdNdAlO₄ or semiconductor substrate.

Claim 7

A process for preparing a thin film of oxide superconductor consists of first portions (11, 12) and second portions (10) each possessing a different crystal orientation on a substrate (2), characterized by the steps of depositing a first buffer layer (3) on said substrate (2), removing selected portions (5) of said first buffer layer (3) to expose a surface of said substrate (2), depositing a second buffer layer (4) on the exposed surface, and then depositing a thin film of oxide superconductor (10, 11, 12) on the first buffer layer (31, 32).remained and on the second buffer layer (4).

Claim 8

The process set forth in claim 7, wherein said first portions (11, 12) consist of c-axis oriented thin films, while said second portions (10) consist of a-axis oriented thin films.

Claim 9

The process set forth in claim 7 or 8, wherein said first buffer layer portions (31, 32) are made of LaAlO₃ or PrGaO₃ and said second buffer layer portions (4) are made of Al₂O₃ or MgO.

Claim 10

The process set forth in any one of claim 7 to 9, wherein said buffer layer portions (31, 32, 4) have a thickness of about 200 nm.

Claim 11

The process set forth in any one of claim 7 to 10, wherein said substrate is MgO (100), SrTiO₃, CdNdAlO₄ or semiconductor substrate.

Claim 12

The thin film of oxide superconductor comprising first portions (10) whose c-axis of crystal is in parallel with a surface of a substrate (2) at first selected area of said surface, and second portions (11, 12) whose c-axis of crystal is perpendicular to said surface at second selected area of said surface, said first portions (10) being deposited on a very thin under-film layer (100) of oxide superconductor whose c-axis of crystal is in parallel with said surface and which is deposited previously on said substrate (2) while said second portions (11, 12) being deposited directly on said substrate (2).

Claim 13

The thin film set forth in claim 13, wherein said first portions (11, 12) consist of c-axis oriented thin films, while said second portions (10) consist of a-axis oriented thin films.

Claim 14

The thin film set forth in claim 13 or 14, wherein said underfilm layer (100) have a thickness less than 50 nm.

Claim 15

The thin film set forth in any one of claim 13 to 15, wherein said substrate (2) is MgO (100), SrTiO₃, CdNdAlO₄ or semiconductor substrate.

Claim 16

A process for preparing a thin film of oxide superconductor possessing locally different crystal orientations on a substrate, said thin film having first portions (10) whose c-axis of crystal is in parallel with a surface of said substrate (2) at first selected area of said surface and second portions (11, 12) whose c-axis of crystal is perpendicular to said surface at second selected area of said surface, characterized by the steps of covering said second selected area with a sublimatable metal (60) having a higher sublimation temperature than a film forming temperature of said second portions (11, 12), depositing a very thin under-film layer (100, 101, 102) of oxide superconductor whose c-axis of crystal is in parallel with said surface whole over said surface, elevating a substrate temperature to sublimate said metal to remove parts of said under-film layer (101, 102) and then deposing a thin film of oxide superconductor (10, 11, 12) under such a condition that is suitable to effect growth of a c-axis oriented thin film of oxide superconductor.

Claim 17

The process set forth in claim 17, wherein said sublimatable metal (60) is Mo.

Claim 18

The process set forth in claim 17 or 18, wherein said substrate is heated about 790 °C to sublimate said metal.

Claim 19

The process set forth in any one of claim 17 to 19, wherein said thin film of oxide superconductor (10, 11, 12) is prepared by off-axis sputtering.