Improved ferrite memory cores obtained by a new preparation technique

A new technique for the preparation of very homogeneous ferrite powders of compositions in the MgMnZn system is described. It is based on decomposition of a solidified concentrated solution of organometallic salts. During this process no segregation of the components occurs. The benefits resulting from the new process are as follows: 1) Highly rectangular loops with low switching coefficients are obtained. 2) As a result, greater amounts of zinc than heretofore employed can be incorporated into the ferrite before the rectangularity falls to unusable values. 3) Therefore, lower drive currents are made possible without drastic increases in switching time (an 18 mil core with a drive current of 300 mA under the 0.61 disturb condition and a switching time of 280 ns can be produced). 4) Further reductions in switching time can be made by decreasing the rise time and using partial switching. 5) The poorer temperature coefficients that always result with incorporation of zinc can be offset by the inclusion of a small amount of cobalt.