Magnetic memory device, method for writing into magnetic memory device and method for reading magnetic memory device

A magnetic memory device comprising:

• a first signal line extended in a first direction;
• a second signal line extended in the first direction;
• a plurality of third signal lines extended in a second direction intersecting the first direction;
• a plurality of memory cells each disposed, associated with the third signal lines and each including a first parallelly connected set which is disposed at an intersection of the first signal line and the third signal line and including
• a first magnetoresistive effect element and a first select transistor parallelly connected to each other and having one end connected to the first signal line, and
• a second parallelly connected set which is disposed at an intersection of the second signal line and the third signal line and including a second magnetoresistive effect element and a second select transistor parallelly connected to each other and having one end connected to the second signal line;
• and
• a read circuit connected to the first signal line and the second signal line, for reading information memorized in the memory cells, based on voltages of the first signal line and the second signal line,
• a plurality of said memory cells forming a basic cell block including
• a first NAND-type cell block which is formed of the first parallelly connected sets serially connected to each other and has one end connected to the first signal line and the other end connected to a ground line, and
• a second NAND-type cell block which is formed of the second parallelly connected sets serially connected to each other and has one end connected to the second signal line and the other end connected to the ground line.

A method for writing into a magnetic memory device comprising a first signal line extended in a first direction;

• a second signal line extended in the first direction;
• a third signal line extended in a second direction intersecting the first direction;
• a memory cell including a first parallelly connected set which is disposed at an intersection of the first signal line and the third signal line and including a first magnetoresistive effect element and a first select transistor parallelly connected to each other and having one end connected to the first signal line, and a second parallelly connected set which is disposed at an intersection of the second signal line and the third signal line and including a second magnetoresistive effect element and a second select transistor parallelly connected to each other and having one end connected to the second signal line, the method comprising:
• flowing a first write current through the first signal line, flowing through the second signal line a second write current in a direction opposite to a direction of flow of the first write current, and flowing a third write current through the third signal line, whereby a writing is made in a memory cell that resistance states of the first magnetoresistive effect element and the second magnetoresistive effect element have a complementary state.

A method for reading a magnetic memory device comprising a first signal line extended in a first direction;

• a second signal line extended in the first direction;
• a plurality of third signal lines extended in a second direction intersecting the first direction;
• a plurality of memory cells each disposed, associated with the third signal lines and each including a first parallelly connected set which is disposed at an intersection of the first signal line and the third signal line and including a first magnetoresistive effect element and a first select transistor parallelly connected to each other and having one end connected to the first signal line, and a second parallelly connected set which is disposed at an intersection of the second signal line and the third signal line and including a second magnetoresistive effect element and a second select transistor parallelly connected to each other and having one end connected to the second signal line, and forming a first NAND-type cell block which is formed of the first parallelly connected sets serially connected to each other and has one end connected to the first signal line and a second NAND-type cell block which is formed of the second parallelly connected sets serially connected to each other and has one end connected to the second signal line and the other, the method comprising:
• turning off the first select transistor and the second select transistor of a memory cell to be read and turning on the first select transistors and the second transistors of the other memory cells;
• flowing a first sense current through the first NAND-type cell block via the first signal line to thereby output to the first signal line a first output voltage reflecting a resistance state of the first magnetoresistive effect element of the memory cell to be read;
• flowing a second sense current equal to the first sense current through the second NAND-type cell block via the second signal line to thereby output to the second signal line a second output voltage reflecting a resistance state of the second magnetoresistive effect element of the memory cell to be read;
• and
• amplifying and comparing the first output voltage and the second output voltage by a sense circuit to thereby read information memorized in the memory cell.