Liquid phase epitaxy spacing layer is compatible with systems which are hard-bubble proofed by use of second magnetic garnet film as capping layer. Composite is superior in that: circuit fabrication time is reduced; adherence is superior; visibility is better; and, good match of thermal expansion coefficients is provided

Moody, J. W.

Sanfort, R. M.

Shaw, R. W.

English

NASA Technical Reports Server

January 1975	 B74-10262 
NASA TECH BRIEF 
Langley Research Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. . They are issued to encourage 
commercial application. Tech Briefs are available on a subscriptior basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Depositing Spacing Layers on Magnetic Film With Liquid Phase Epitaxy 
Research conducted for Langley Research Center 
has revealed that liquid phase epitaxy can be used to 
deposit spacing layers on magnetic films. This 
consists of depositing, by liquid phase epitaxy, a thin 
film of Gd 3Ga 5O 12 on a ferrimagnetic garnet film, to 
provide a spacing layer between the garnet film and 
the Permalloy drive circuit used in magnetic bubble 
devices. The Gd 3Ga 5O 12 (GGG) spacing layer cannot 
be used if ion implantation is used to "hard-bubble 
proof' the magnetic film, as the effects of ion 
implantation would be destroyed as soon as the film is 
immersed in the solution. However, the liquid phase 
epitaxy GGG spacing layer is compatible with systems 
which are hard-bubble proofed by the use of a second 
magnetic garnet film as a capping layer. 
The GGG substrate-magnetic film-GGG spacing 
layer composite is superior to more conventional 
layers in such important respects as the following: 
1. Circuit fabrication time is reduced; 
2. Gd 3Ga 5O 12 absorbs less in the visible spectrum, 
resulting in better visibility; 
3. Adherence is superior; and 
4. A good match of thermal expansion coefficients 
is provided. 
In a bubble device, the Permalloy circuit is 
separated from the magnetic film by a thin non-
magnetic spacing layer. Conventional spacing layers 
are not suitable for use in devices subjected to wide 
temperature applications, as their thermal expansion 
coefficients do not match the expansion coefficient of 
the garnet. A magnetic film sandwiched between a 
substrate and a spacing layer of the same composition 
provides a closer approach to the ideal composite
structure. The depositing, by liquid phase epitaxy, of 
Gd 3Ga 50 12 spacing layers on the magnetic film 
provides a more compatible substrate-magnetic film-
spacing layer system. 
The films were grown with rotation by the 
isothermal dipping method and were deposited on 
Syton-polished GGG substrates as well as on a variety 
of magnetic film compositions. The presence of the 
GGG spacing layer did not affect, significantly, the 
magnetic properties of the bubble domain film. 
Permalloy propagation circuits were fabricated on 
Gd 09Er21Fe4Ga06O 12 magnetic film-GGG spacing 
layer combinations, and domains were propagated 
readily. The GGG spacing layers were found to be 
superior to conventional materials in the above-
mentioned areas. 
Notes: 
1. The following documentation, outlining experi-
mentation and results, may be obtained from: 
National Technical Information Service 
Springfield, Virginia 22151 
Single document price $4.25 
(or microfiche $2.25) 
Reference: NASA CR-2413 (N74-30206), In-
vestigation of the Growth of Garnet Films By 
Liquid Phase Epitaxy 
2. Technical questions may be directed to: 
Technology Utilization Officer 
Langley Research Center 
Mail Stop 139-A 
Hampton, Virginia 23665 
Reference: B74-10262 
•	 .	 .	 .	
.	 (contInMed overleaf) 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19740000262 2020-03-17T13:58:11+00:00Z
Patent status: 
NASA has decided not to apply for a patent. 
Source: Jerry W. Moody, Roger W. Shaw,

and Robert M. Sandfort of

Monsanto Research Corp.

under contract to

Langley Research Center

(LAR-1 1528)
a 
Categories: 01 (Electronics - Components and 
Circuitry) 
03 (Physical Sciences) 
04 (Materials)	 0 
08 (Fabrication Technology) B74-10262


Depositing spacing layers on magnetic film with liquid phase epitaxy

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