Physical Sciences and Mathematics Commons^™

A Non-Erasable Magnetic Memory Based On The Magnetic Permeability, J R. Petrie, K A. Wieland, R A. Burke, G A. Newburgh, J E. Burnette, G A. Fisher, A S. Edelstein

United States Army: Publications

A non-erasable memory based on using differences in the magnetic permeability is demonstrated. The method can potentially store information indefinitely. Initially the high permeability bits were 10–50 μm wide lines of sputtered permalloy (Ni₈₁Fe₁₉) on a glass substrate. In a second writing technique a continuous film of amorphous, high permeability ferromagnetic Metglas (Fe78Si13Bg) was sputtered onto a similar glass substrate. Low permeability, crystalline 50 Jlm wide lines were then written in the film by laser heating. Both types of written media were read by applying an external probe field that is locally modified by the permeability …