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Transparent Ferrimagnetic Fluorides

IP.com Disclosure Number: IPCOM000092167D
Original Publication Date: 1968-Oct-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Shafer, MW: AUTHOR

Abstract

These transparent, ferrimagnetic compositions have the general formula RbM(1-x)B(x)F(3) where B is cobalt or iron. The ferrimagnetic compositions have the hexagonal crystal structure and can be prepared as single crystals. The compositional range where ferrimagnetism is obtained is 0.3

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Transparent Ferrimagnetic Fluorides

These transparent, ferrimagnetic compositions have the general formula RbM(1-x)B(x)F(3) where B is cobalt or iron. The ferrimagnetic compositions have the hexagonal crystal structure and can be prepared as single crystals. The compositional range where ferrimagnetism is obtained is 0.3 </- x </- 0.7 in the cobalt system and 0.3 </- x </- 0.35 in the iron system. The cobalt compositions have Curie temperatures as high as 38 degrees K and magnetic moments which increase with Co++ concentration to a value of 23 emu/gram. These materials are optically transparent at visible wavelengths and have their easy axis of magnetizations parallel to the c axis of the hexagonal crystal. They have extremely high anisotropies, e.g., over 200 kOe are necessary to change the direction of magnetization to the a plane. The compositions are prepared by heating pellets consisting of a mixture of RbF, MgF(2) and CoF(2), in desired proportions, in a platinum crucible. Heating is at 600-700 degrees C and is maintained for about 12 hours. After heating, the composition is allowed to cool slowly to room temperature to form a polycrystalline powder. The crystalline powder is heated to 975 degrees C and then slowly cooled for 6-8 hours from 975 degrees C to about 775 degrees C. When 775 degrees C is reached, the crucible is gradually cooled for 1-2 hours to room temperature. Large single crystals are thus formed which are cut, polished and oriented for use...