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Magnetic Bubble Garnets on Aluminate Substrates

IP.com Disclosure Number: IPCOM000078560D
Original Publication Date: 1973-Jan-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Giess, EA: AUTHOR

Abstract

Garnet substrates utilized in magnetic bubble domain structures are difficult to grow and contain high cost Ga(2)O(3). A low-cost class of garnets is suggested which is comparable with inexpensive aluminate substrates.

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Magnetic Bubble Garnets on Aluminate Substrates

Garnet substrates utilized in magnetic bubble domain structures are difficult to grow and contain high cost Ga(2)O(3). A low-cost class of garnets is suggested which is comparable with inexpensive aluminate substrates.

The aluminate garnets, e.g., Gd(3)Al(5)O(12) have higher melting points than gallate garnets, but they can be grown in crucibles other than iridium, which is very expensive. Aluminates have been grown in tungsten crucibles under neutral atmosphere. Also, the aluminates are not volatile, whereas gallates form Ga(2)O, which is volatile.

Gd(3)Al(5)O(12) (GAG) has an a(o) = 12.111 which is significantly smaller than that of the magnetic film compositions now in use. However, it is possible to select the heavier rare earth garnets, which have smaller a(o), for "fitting" aluminate garnet substrates. Lu(3)Fe(5)O(12) and Yb(3)Fe(5)O(12) would be preferred magnetic garnet base compositions. Doping these garnets with Eu/3+/ or Tb/3+/ would produce the required uniaxial anisotropy with (111) orientation for stabilizing bubbles, and would allow the use of film compositions with lattice parameters slightly greater than the a(o) = 12.111 of GAG. To adjust 4 pi M, Al/3+/ would be substituted for Fe/3+/. This substitution would further reduce the film a(o) and allow the use of a greater range of film compositions. A typical film composition might be Eu(.5)Lu(2.5)Fe(4)AlO(12).

The lattice constant of Gd(3)Al(5)O(12) c...