Nonvolatile magnetoresistive memory with fully closed flux operation

A device for storing information comprising:

• an array of storage elements arranged in columns and rows, each storage element comprising,
• a first structure having a plurality of layers, selected layers having magnetization vectors associated therewith, the first structure exhibiting giant magnetoresistance, wherein each storage element has a closed flux structure in at least one dimension, and wherein the magnetization vectors are substantially confined to the at least one dimension during all stages of operation of the storage element;
• a plurality of read and write conductors for reading information from and writing information to the array of storage elements, each read and write conductor being for reading from and writing to a particular row of storage elements;
• and
• a plurality of selection conductors for applying selection signals to the array of storage elements, each selection conductor being for selecting a particular column of storage elements and enabling reading from and writing to the storage elements of the particular column;
• wherein random access to any of the storage elements may be effected by the concurrence of signals on corresponding ones of the read and write conductors and the selection conductors.

A thin-film memory cell, comprising:

• a multilayer thin-film storage element exhibiting giant magnetoresistance, the storage element having a top, a bottom, an aperture therethrough, and a magnetization around the aperture;
• a thin-film word line passing through the aperture, the thin-film word line being electrically isolated from the thin-film storage element;
• and
• a segmented thin-film sense/digit line having two segments coupled to the thin-film storage element such that current flowing through the thin-film sense/digit line passes through the thin-film storage element, the sense/digit line exhibiting a resistance which depends on orientations of magnetization vectors in the multilayer thin-film storage element;
• wherein the magnetization in the thin-film storage element is switched from a clockwise direction around the aperture to a counterclockwise direction around the aperture and from a counterclockwise direction around the aperture to a clockwise direction around the aperture in response to a coincidence of current in the segmented sense/digit line and the word line, the magnetization of the thin-film storage element having a closed flux orientation during substantially all stages of operation of the thin-film storage element.

A thin-film memory cell, comprising:

• a multilayer thin-film storage element exhibiting giant magnetoresistance, the storage element having an aperture therethrough, and a magnetization around the aperture;
• a thin-film word line passing through the aperture, the thin-film word line being electrically isolated from the thin-film storage element;
• a thin-film digit line passing through the aperture, the thin-film digit line being electrically isolated from the thin-film storage element;
• and
• a segmented thin-film sense line having two segments coupled to the thin-film storage element such that current flowing through the thin-film sense line passes through the thin-film storage element, the sense line exhibiting a resistance which depends on orientations of magnetization vectors in the multilayer thin-film storage element;
• wherein the magnetization in the thin-film storage element is switched from a clockwise direction around the aperture to a counterclockwise direction around the aperture and from a counterclockwise direction around the aperture to a clockwise direction around the aperture in response to a coincidence of current in the digit line and the word line, the magnetization of the thin-film storage element having a closed flux orientation during substantially all stages of operation of the thin-film storage element.

A thin-film memory cell, comprising:

• a multilayer thin-film storage element exhibiting giant magnetoresistance;
• a thin-film word line deposited on top of the thin-film storage element and electrically isolated therefrom;
• a serpentine thin-film digit line deposited on top of the thin-film word line and parallel to the thin-film word line in an area over the thin-film storage element, the thin-film digit line being electrically isolated from both the thin-film storage element and the thin-film word line;
• a keeper element of magnetic material deposited on top of the thin-film storage element, the thin-film word line, and the thin-film digit line, the keeper element being electrically isolated from the thin-film word line and the thin-film digit line;
• and
• a segmented thin-film sense line having two segments coupled to the thin-film storage element such that current flowing through the thin-film sense line passes through the thin-film storage element, the sense line exhibiting a resistance which depends on orientations of magnetization vectors in the multilayer thin-film storage element;
• wherein the magnetization in the thin-film storage element is switched from a clockwise direction around the word and digit lines to a counterclockwise direction around the word and digit lines and from a counterclockwise direction around the word and digit lines to a clockwise direction around the word and digit lines in response to a coincidence of current in the digit line and the word line, the magnetization of the thin-film storage element having a closed flux orientation during substantially all stages of operation of the thin-film storage element.

A thin-film memory cell comprising:

• a multilayer thin-film storage element exhibiting giant magnetoresistance, the storage element being characterized by a magnetization, and having a region associated therewith;
• a thin-film sense line electrically connected to the storage element such that current in the sense line flows through the storage element;
• a thin-film digit line;
• and
• a thin-film word line electrically isolated from the storage element and the digit line, the word line being oriented substantially parallel to the digit line in the region of the storage element;
• wherein the magnetization in the storage element is switched from a clockwise direction around the word and digit lines to a counterclockwise direction and from the counterclockwise direction around the word and digit lines to the clockwise direction in response to a coincidence of current in the word and digit lines, the magnetization being confined to a closed flux structure during all stages of operation of the memory cell.

A device for storing information comprising:

• an array of storage elements arranged in columns and rows, each storage element comprising,
• a first structure having a plurality of layers, selected layers having magnetization vectors associated therewith, the first structure exhibiting giant magnetoresistance, wherein each storage element has a closed flux structure in at least one dimension, and wherein upon application of a half-select current the magnetization vectors of each storage element are substantially confined to the at least one dimension;
• a plurality of read and write conductors for reading information from and writing information to the array of storage elements, each read and write conductor being for reading from and writing to a particular row of storage elements;
• and
• a plurality of selection conductors for applying selection signals to the array of storage elements, each selection conductor being for selecting a particular column of storage elements and enabling reading from and writing to the storage elements of the particular column;
• wherein random access to any of the storage elements may be effected by the concurrence of signals on corresponding ones of the read and write conductors and the selection conductors.