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Preventing the Formation of Dislocation Loops at Inclusions in Crystals of Gd(3)Ga(5)O(12)

IP.com Disclosure Number: IPCOM000078561D
Original Publication Date: 1973-Jan-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Klokholm, E: AUTHOR [+3]

Abstract

If Gd(3)Ga(5)O(12) (GGG) crystals are to be suitable substrates for magnetic garnet films used in bubble domain devices, they should contain no dislocations. A study of dislocations in GGG has shown that most of them are loops associated with the inclusions. A method of preventing the formation of dislocation loops at inclusions is suggested, which consists of doping the GGG with 1 or 2% Gd(2)O(3).

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Preventing the Formation of Dislocation Loops at Inclusions in Crystals of Gd(3)Ga(5)O(12)

If Gd(3)Ga(5)O(12) (GGG) crystals are to be suitable substrates for magnetic garnet films used in bubble domain devices, they should contain no dislocations. A study of dislocations in GGG has shown that most of them are loops associated with the inclusions. A method of preventing the formation of dislocation loops at inclusions is suggested, which consists of doping the GGG with 1 or 2% Gd(2)O(3).

Many of the dislocations present in Gd(3)Ga(5)O(12) crystals grown by the Czochralski technique are associated with iridium inclusions. The dislocations are in the form of large, circular, or almost circular, loops on the {111}, {110} and {100} planes. The inclusions lie at the center of these loops. The loops grow by climb and are of the interstitial variety. The nature of these loops suggests that they are the result of a departure from stoichiometry.

In order to test this, Gd(3)Ga(5)O(12) crystals have been examined which were deliberately doped with 1 or 2% Gd(2)O(3). Examination of these crystals in a polarizing microscope shows that the inclusions are not encircled by dislocations. Thus, the addition of Gd(2)O(3) prevents the formation of the loops. Crystals doped with 1% Gd(3)O(3) differ from those doped with two percent in the magnitudes of the stress fields associated with the inclusions. The inclusions in the crystal with 1% excess Gd(2)O(3) give rise to fairly large el...