Patent ID: 8476925
Filing Date: 2013-07-02
Classification: G11C,H01F,H01L

Abstract:
1. A nonvolatile magnetic switching cell (mCell) having (i) first and second programming terminals for switching the mCell between low and high resistance states in response to currents that flow between said programming terminals and (ii) first and second evaluation terminals that present (a) a first, lower resistance when the mCell is in the low resistance state and (b) a second, higher resistance when the mCell is in the high resistance state, said mCell comprising: first and second magnetized programming electrodes electrically coupled to said respective first and second programming terminals, said first programming electrode having a magnetization substantially opposite to that of said second programming electrode; a magnetic switching layer made from a conductive material with perpendicular magnetic anisotropy, said magnetic switching layer having (i) a first region adjacent said first programming electrode, (ii) a second region adjacent said second programming electrode, and (iii) a domain switching region located between said first and second regions; said first region of said magnetic switching layer electrically coupled to said first programming electrode such that current can flow between said first region and said first programming electrode and magnetically coupled such that the magnetization in said first region is pinned by said magnetization of said first programming electrode; said second region of said magnetic switching layer electrically coupled to said second programming electrode such that current can flow between said second region and said second programming electrode and magnetically coupled such that the magnetization in said second region is pinned by said magnetization of said second programming electrode; said pinned, opposing magnetizations in said first and second regions of said magnetic switching layer creating a domain wall in said domain switching region of said magnetic switching layer, said magnetic switching layer configured such that (i) currents flowing from said first programming electrode to said second programming electrode cause said domain wall to position itself proximate to said first region of said magnetic switching layer, thereby causing most of said domain switching region to assume said magnetization of said second region and causing said mCell to assume said low resistance state, and (ii) currents flowing from said second programming electrode to said first programming electrode cause said domain wall to position itself proximate to said second region of said magnetic switching layer, thereby causing most of said domain switching region to assume said magnetization of said first region and causing said mCell to assume said high resistance state; a switchable magnetic evaluation layer, electrically isolated from and magnetically coupled to said domain switching region of said magnetic switching layer, such that said switchable magnetic evaluation layer follows the magnetization of said domain switching region of said magnetic switching layer; at least a first magnetized evaluation electrode, said first evaluation electrode electrically coupled between said first evaluation terminal and said magnetic evaluation layer; and, at least one magnetic tunnel junction interposed between said first evaluation electrode and said magnetic evaluation layer, such that currents which flow between said evaluation terminals through said magnetic evaluation layer pass through said at least one tunnel junction.