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Ge Pb Substituted Garnet Composition

IP.com Disclosure Number: IPCOM000081846D
Original Publication Date: 1974-Aug-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Klokholm, E: AUTHOR [+2]

Abstract

Pb is used to charge-compensate the Ge addition of garnet films.

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Ge Pb Substituted Garnet Composition

Pb is used to charge-compensate the Ge addition of garnet films.

Ge has been shown heretofore to be more effective in lowering the 4piM(s) than either Ga or Al in garnet films. Whereas Ga and Al substitute in a small degree on the octahedral site as well as the tetrahedral site, Ge substitutes completely on the tetrahedral site. The octahedral substitution raises the 4piM(s) and lowers the Curie temperature, which reduces the bubble mobility. Because Ge is a tetravalent ion, Ca/2+/ or Sr/2+/ is added to maintain charge balance. The divalent ions go on the dodecahedral sites.

Ge-Pb substituted garnet films were grown by dissolving the garnet constituents, e.g., Eu(2)O(3), Y(2)O(3)Fe(2)O(3) in a PbO:B(2)O(3) flux. The Ge is added as GeO(2).

Pb, which is already an impurity in garnet grown from PbO:B(2)O(3) fluxes, is used to charge-compensate for the Ge addition. It is believed that the Ge reduces the Pb content because Ge/4+/ replaces Pb/4+/ and that the Pb is incorporated in the garnet film as Pb/2+/ and Pb/4+/. For example, it was found that the Pb content was 2.5 wt% with the Ge present, and 5.0 wt% without Ge present.

The charge is heated to about 1250 degrees C to dissolve the constituents, and then is slowly lowered to the growth temperature of between 750 degrees C and 800 degrees C which is required to ensure sufficient Pb incorporation in the film. The Pb content in the films generally increases as the growth temperatu...