Voltage-controlled magnetization reversal writing type magnetic random access memory device and method of writing and reading information using the same

A method of writing information using a voltage-controlled magnetization reversal writing type MRAM device, comprising:

• the step S1-1 of applying voltage to writing lines comprising a positive electrode and a negative electrode of the MRAM device;
• the step S1-2 of generating an electric field in a piezoelectric layer located between the writing lines;
• the step S1-3 of inducing distortion of the piezoelectric layer using the electric field generated in the piezoelectric layer;
• the step S1-4 of changing a free ferromagnetic layer, which is disposed on the piezoelectric layer, from a horizontal magnetization state to a vertical magnetization state using the distortion induced in the piezoelectric layer;
• and
• the step S1-5 of writing variation in magnetization generated in the free ferromagnetic layer.

A method of reading information using a voltage-controlled magnetization reversal writing type MRAM device, comprising:

• the step S2-1 of applying current to either of two electrically conductive reading lines disposed to be perpendicular to each other;
• the step S2-2 of sequentially transferring the applied current to an antiferromagnetic layer, a pinned ferromagnetic layer, and a nonmagnetic layer and a free ferromagnetic layer;
• the step S2-3 of relatively varying resistance, which is caused by the transferred current, depending on directions of magnetization of the free ferromagnetic layer and the pinned ferromagnetic layer;
• and
• the step S2-4 of reading a magnetization state generated in the free ferromagnetic layer.

A method of writing and reading information using a voltage-controlled magnetization reversal writing type MRAM device, comprising:

• a writing process comprising the step S1-1 of applying voltage to writing lines comprising a positive electrode and a negative electrode of the MRAM device, the step S1-2 of generating an electric field in a piezoelectric layer located between the writing lines, the step S1-3 of inducing distortion of the piezoelectric layer using the electric field generated in the piezoelectric layer, the step S1-4 of changing a free ferromagnetic layer, which is disposed on the piezoelectric layer, from a horizontal magnetization state to a vertical magnetization state using the distortion induced in the piezoelectric layer, and the step S1-5 of writing variation in magnetization generated in the free ferromagnetic layer;
• and
• a reading process comprising the step S2-1 of applying current to either of two electrically conductive reading lines disposed to be perpendicular to each other, the step S2-2 of sequentially transferring the applied current to an antiferromagnetic layer, a pinned ferromagnetic layer, and a nonmagnetic layer and a free ferromagnetic layer, the step S2-3 of relatively varying resistance, which is caused by the transferred current, depending on directions of magnetization of the free ferromagnetic layer and the pinned ferromagnetic layer, and the step S2-4 of reading a magnetization state generated in the free ferromagnetic layer;
• wherein the reading and writing are independently performed by the two writing lines and the two reading lines, respectively.