Epitaxial growth of M-type hexagonal ferrite films on spinel substrates and composite

• US 4,189,521 A
• Filed: 07/05/1977
• Issued: 02/19/1980
• Est. Priority Date: 07/05/1977
• Status: Expired due to Term

• Current Assignee: Rockwell International Corporation
• Original Assignee: Rockwell International Corporation
• Inventors: Glass, Howard L., Heinz, David M., Stearns, Frederick S.
• Primary Examiner(s): Kittle, John E.
• Application Number:
  US05/812,862
• Time in Patent Office: 959 Days
• Field of Search: 428/469, 428/471, 428/472, 428/539, 23/DIG. 1, 156/622, 156/624, 156/DIG. 74, 156/77, 156/78, 252/62.56, 252/62.62, 252/62.63, 423/594, 333/24.1, 333/24.2, 350/96 M, 350/96 WG
• US Class Current: 428/842.8
• CPC Class Codes: C04B 35/2633 containing barium, strontium or calcium
• CPC Class Codes: C30B 19/02 using molten solvents, e.g. flux
• CPC Class Codes: C30B 29/22 Complex oxides
• CPC Class Codes: Y10S 423/12 Molten media

Abstract

M-type hexagonal ferrites whose prototype chemical formula (BaFe₁₂ O₁₉) contains no zinc and W-type hexagonal ferrites whose prototype chemical formula is (BaZn₂ Fe₁₆ O₂₇) can be successfully grown by LPE on spinel substrates having appropriate lattice parameters when controlled quantities of the zinc are present in the melts from which these hexagonal ferrites are grown. Using this growth technique, composites comprising a monocrystalline magnetic M-type or W-type hexagonal ferrite film on a non-magnetic single crystalline spinel substrate are provided.

Claims

1. A composite comprising:

a monocrystalline nonmagnetic spinel substrate having a lattice constant in the range from 8.309A to 8.381A, and

a film of hexagonal ferrite selected from the group consisting of M-type and W-type epitaxially disposed on said substrate.

2. The composite recited in claim 1 wherein said substrate is selected from the group consisting of MgIn_X Ga_2-X O₄ 0.19≦

X≦

0.38 and ZnGa₂ O₄.

3. The composite recited in claim 2 wherein said film is M-type.

4. The composite recited in claim 1 wherein said film is W-type and said substrate is selected from the group consisting of MgIn_X Ga_2-X O₄, 0.19≦

X≦

0.38.

8. The composite recited in claim 1 wherein

said film disposed on said substrate is discontinuous.

9. The composite recited in claim 1 wherein said film is disposed on the (111) crystallographic plane of said spinel substrate.

5. A method of epitaxially depositing an hexagonal ferrite film on a non-magnetic spinel substrate by liquid phase epitaxy said method comprising:

forming a fluxed melt containing quantities of barium, iron and oxygen suitable for epitaxially growing said film;

including in said melt a quantity of zinc which provides a zinc oxide to iron oxide ratio in the range between 0.1332 and 0.4630 moles of zinc oxide per mole of iron oxide;

contacting said melt with a spinel-type substrate having a lattice constant in the range from 8.309A to 8.381A and holding said melt at a temperature below its saturation temperature for a period of time sufficient to grow a desired thickness of said hexagonal ferrite on said substrate.

6. The method recited in claim 5 wherein said substrate is selected from the group consisting of MgIn_X Ga_2-X O₄, 0.19≦

X≦

0.38 and ZnGa₂ O₄.

7. The method recited in claim 5 wherein the growth of said film is terminated while the film comprises a plurality of isolated M-type hexagonal ferrite islands epitaxially disposed on said substrate.

10. The method recited in claim 5 wherein

said film is M-type hexagonal ferrite when said ratio is between 0.1332 and 0.4118 moles.

11. The method recited in claim 5 wherein

said film is W-type hexagonal ferrite when said ratio is between 0.4118 and 0.4630.