in one embodiment of the invention , there is provided a method for operating a magnetic memory device . the method comprises selecting a subset of magnetic memory cells of the magnetic memory device ; applying a first programming voltage to the selected subset of cells for a predetermined amount of time , wherein the programming voltage is selected to exceed a threshold operating voltage thereby to cause irreversible breakdown of the subset of cells ; and reading selected cells of the magnetic memory device by passing a read current through a diode connected in series with each magnetic memory cell .