At&t Bell Laboratories

Bell Telephone Laboratories

American Telephone & Telegraph Co., At&t Bell Laboratories

Lars C Luther

Terence J Nelson

Ernst M Gyorgy

Stuart L Blank

Roy C LeCraw

Roy Conway Le Craw

Charles D Brandle, Jr

Virendra V Rana

Vincent J Fratello

Susan E Slusky

Virendra V Singh Rana

High magnetic anisotropy is achieved in bismuth-iron garnet materials which comprise a significant amount of europium, samarium, or terbium. Such materials may be made in the form of epitaxial layers grown on a nonmagnetic substrate, e.g., in the manufacture of magnetic bubble devices. On account of significant Faraday rotation, such materials may also be used in magnetic-optical devices.

Bismuth-iron garnets with large growth-induced magnetic anisotropy

Epitaxial layers of bismuth-containing magnetic garnet materials are grown from a melt which comprises flux components lead oxide, bismuth oxide, and one or several additional oxides selected from vanadium oxide, tungsten oxide, molybdenum oxide, and chromium trioxide. The presence of such additional flux component results in increased magnetic anisotropy per degree of supercooling and thus enhances device properties and facilitates epitaxial layer deposition.

Liquid phase epitaxial growth of bismuth-containing garnet films

Yttrium-iron magnetic domain materials having bismuth ions on dodecahedral sites are suitable for the manufacture of high-density, high-speed magnetic domain devices for operation at high and especially at very low temperatures. In these devices magnetic domain velocity is greater than 2000 centimeters per second per oersted, and magnetic domain diameter is less than 3 micrometers. A specified operational temperature range may extend from -150 to 150 degrees C.; accordingly, such devices are particularly suitable for operation aboard satellites, e.g., in satellite communications systems.

Magnetic domain device having a wide operational temperature range

Epitaxial layers of bismuth containing magnetic garnet materials are grown from a melt which comprises flux components lead oxide, bismuth oxide, and one or several additional oxides selected from vanadium oxide, tungsten oxide, and molybdenum oxide. The presence of such additional flux component results in increased magnetic anisotropy per degree of supercooling and thus enhances device properties and facilitates epitaxial layer deposition.

Devices based on epitaxial garnet layers that exhibit a high magnetic anisotropy are disclosed. These garnet layers are produced by introducing a Co.sup.2+ or a species with 1, 2, 4, or 5 electrons in a 4d or a 5d electron orbital in the octahedral site of the garnet in conjunction with a typical anisotropy producing combination on the dodecahedral site. The contribution to magnetic anisotropy due to the typical combination on the dodecahedral site and the appropriate ion in an octahedral site is complementary.

Devices depending on garnet materials

Devices based on epitaxial garnet layers which exhibit a substantial contribution to the magnetic anisotropy other than that attributable to the presence of magnetic rare earth ions are disclosed. These garnet layers are produced by introducing Co.sup.2+ or a species with 1, 2, 4, or 5 electrons in a 4d or 5d electronic orbital in the octahedral site of the garnet. It is possible to produce epitaxial garnets having low damping constants, as determined by resonance line widths on the order of 100 Oe, and K.sub.u 's on the order of 300,000 ergs/cm.sup.3.

Growing community of inventors

Basking Ridge, NJ, United States of America

Lars C Luther