Multi-layer magnetic tunneling junction memory cells

A multi-state, multi-layer magnetic memory cell comprising:

• first and second layers of magnetic material each having a width that is less than a width of magnetic domain walls within the layer of magnetic material wherein magnetic vectors in the layers of magnetic material point along a length of the layers of magnetic material;
• a layer of insulating material sandwiched between the first and second layers of magnetic material so as to form a multi-layer magnetic memory cell;
• and
• an electrically conductive word line positioned adjacent the multi-layer magnetic memory cell so as to provide a magnetic field, when the word line is activated, to at least partially switch the magnetic vectors in one of the first and second layers of magnetic material from a first direction along the length of the one to a second, opposite direction along the length of the one.

An array of multi-state, multi-layer magnetic memory cells comprising:

• a substrate having a surface;
• a plurality of multi-layer magnetic memory cells supported on the substrate and defining rows and columns of multi-layer magnetic memory cells, each multi-layer magnetic memory cell of the plurality of multi-layer magnetic memory cells including
• a first electrically conductive portion positioned adjacent the surface of the substrate,
• a first layer of magnetic material supported on the substrate in electrical contact with the first electrically conductive portion,
• a layer of insulating material positioned on the first layer of magnetic material,
• a second layer of magnetic material positioned on the layer of insulating material, and
• a second electrically conductive portion positioned in electrical contact with the second layer of magnetic material, the first layer of magnetic material, the layer of insulating material and the second layer of magnetic material forming a multi-layer magnetic memory cell with the first and second electrically conductive portions forming a circuit in conjunction with the cell;
• and
• a plurality of electrically conductive word lines, one each associated with each column of multi-layer magnetic memory cells, the associated word line in each column being positioned adjacent each multi-layer magnetic memory cell in the column so as to provide a magnetic field to each multi-layer magnetic memory cell in the column.

A method of storing and sensing stored information in a multi-state, multi-layer magnetic memory cell comprising the steps of:

• providing a multi-layer magnetic memory cell including a first electrically conductive portion, a first layer of magnetic material contacting the first electrically conductive portion, a layer of insulating material positioned on the first layer of magnetic material, a second layer of magnetic material positioned on the layer of insulating material, a second electrically conductive portion positioned in electrical contact with the second layer of magnetic material, and positioning an electrically conductive word line adjacent the multi-layer magnetic memory cell so as to provide a magnetic field, when the word line is activated, to partially switch magnetic vectors in the first layer of magnetic material from a first direction along a length of the first layer to a second, opposite direction, along the length of the first layer;
• setting magnetic vectors in the second layer of magnetic material in the first direction;
• storing information by producing a magnetic field around the multi-layer magnetic memory cell such that magnetic vectors in the first and second layers of magnetic material are parallel and in the first direction for a first logic symbol and in the second direction for a second logic symbol, the multi-layer magnetic memory cell producing a low resistance between the first and second electrically conductive portions for the first logic symbol and the second logic symbol and a high resistance when the magnetic vectors are antiparallel;
• and
• sensing stored information in the multi-layer magnetic memory cell by determining a resistance between the first and second electrically conductive portions.