Intrinsic magnetic properties promise more secure computer memory

A new method of creating magnetic memory could lead to more robust and secure systems that are not affected by heat or magnetic fields, for applications such as credit and ID cards that cannot be read by passers-by. Rather than encoding data by creating a pattern on a magnetic material using another magnet, this technique, which has been developed by researchers from the US Army and Naval Research Labs, Corning and the University of Nebraska, changes the intrinsic properties of a material in a way that cannot be simply changed and requires proximity to read.

The technique works by changing the magnetic permeability of the memory material: that is, its ability to become magnetised.  Magnetic permeability is a property of materials known as ‘soft’ ferromagnets, in which the magnetic field can be reversed easily. Generally alloys of nickel and iron, they are used the cores of electrical transformers to reduce energy loses associated with the rapidly-reversing magnetic fields of conductors carrying alternating current.