Colloidal Solution Of Fe(3)O(4) For Locating Magnetic Defects
Original Publication Date: 1980-Jan-01
Included in the Prior Art Database: 2005-Feb-12
Due to the size of the magnetic bit cell employed today in magnetic recording, and the size of the magnetic defects, ordinary suspensions of Fe(3)O(4) in water, fluorocarbon, alcohol or other solvent cannot precisely locate the bit cell. Ordinary suspensions also have a hiding power that prevents the identification of the magnetic error. Using a colloidal suspension of Fe(3)O(4), particle size 20 to 800 A and a pigment binder concentration of approximately 0.1% in a solvent such as water, alcohol, fluorocarbon or the like, bit cells of the order of 9 sq. microns can be developed with a high degree of precision. The Fe(3)O(4) particles appear transparent to the optical microscopic analysis so that they do not hide or mask the defects.