Magnetoresistive random access memory with reduced switching field

A magnetoresistive tunneling junction memory cell with a switching field, the cell comprising:

• a first magnetic region having a resultant magnetic moment vector fixed in a preferred direction in the absence of an applied magnetic field wherein the first magnetic region has a thickness and a magnetic fringing field;
• an electrically insulating material positioned on the first magnetic region to form a magnetoresistive tunneling junction;
• a second magnetic region positioned on the electrically insulating material, the second magnetic region having an anisotropy easy axis and a resultant magnetic moment vector oriented In a position parallel or anti-parallel to that of the first magnetic region;
• wherein the magnetoresistive tunneling junction memory cell operates in a toggle writing mode;
• wherein the magnetic fringing field creates a bias field along the anisotropy easy axis and within the second magnetic region;
• and
• wherein at least one of the first and second magnetic regions include a synthetic anti-ferromagnetic layer material that has an adjustable magnetic switching volume wherein the synthetic anti-ferromagnetic layer material includes N ferromagnetic layers which are anti-ferromagnetically coupled, where N is a whole number greater than or equal to two.

A magnetoresistive tunneling junction memory cell with a switching field, the cell comprising:

• a first magnetic region with a thickness, the first magnetic region having a resultant magnetic moment vector fixed in a preferred direction in the absence of an applied magnetic field wherein the first magnetic region has a magnetic fringing field;
• an electrically insulating material positioned on the first magnetic region to form a magnetoresistive tunneling junction;
• a second magnetic region positioned on the electrically insulating material and having an anisotropy easy axis and a resultant magnetic moment vector oriented in a position parallel or anti-parallel to that of the first magnetic region and wherein at least one of the first and second magnetic regions include N ferromagnetic layers which are anti-ferromagnetically coupled, where N is a whole number greater than or equal to two;
• wherein the magnetoresistive tunneling junction memory cell is configured to operate in a toggle writing mode;
• and
• wherein the magnetic fringing field creates a bias field along the anisotropy easy axis and within the second magnetic region.

A method of reducing a switching field for a magnetoresistive tunneling junction memory cell comprising the steps of:

• providing a substrate defining a surface;
• supporting a pinned magnetic region having a thickness, a magnetic switching volume, and a resultant magnetic moment vector on the substrate wherein the resultant magnetic moment vector is oriented in a preferred direction both with and without an applied magnetic field, wherein the pinned magnetic region has a magnetic fringing field;
• positioning an electrically insulating material on the pinned magnetic region;
• positioning a free magnetic region having an is easy axis, a resultant magnetic moment vector, and a magnetic switching volume on the electrically insulating material wherein the resultant magnetic moment vector can be oriented one of parallel and anti-parallel with respect to the resultant magnetic moment vector of the pinned magnetic region, the free magnetic region includes a synthetic anti-ferromagnetic layer material which includes N ferromagnetic layers that are anti-ferromagnetically coupled, where N is a whole number greater than or equal to two and where each N ferromagnetic layer has a magnetic moment vector and the magnetic moment vectors of each adjacent N layer of ferromagnetic material are oriented. anti-parallel wherein the magnetic fringing field creates a bias field within the free magnetic region,
• operating the magnetoresistive tunneling junction memory cell to operate in a toggle writing mode.