Magnetic memory device

1. A magnetic memory device comprising:

a first magnetoresistive element which takes a high-resistance state when receiving a write current in a first direction, takes a low-resistance state having a resistance value lower than a resistance value in the high-resistance state when receiving a write current in a second direction opposite to the first direction, and receives a read current in a read operation;

a second magnetoresistive element which takes one of the high-resistance state and the low-resistance state in accordance with a magnetization state thereof, is fixed to the low-resistance state when a direction of the read current is the same as the first direction, and is fixed to the high-resistance state when the direction of the read current is the same as the second direction; and

a control circuit which is connected to the first magnetoresistive element and the second magnetoresistive element, and makes a read voltage applied to the first magnetoresistive element equal to a read voltage applied to the second magnetoresistive element.

2. The device according to claim 1 , wherein the first magnetoresistive element and the second magnetoresistive element have combinations of identical films, and have the same shape.

3. The device according to claim 1 , wherein the first magnetoresistive element and the second magnetoresistive element include a fixed layer made of a ferromagnetic material, an interlayer made of a nonmagnetic material, and a free layer made of a ferromagnetic material.

4. The device according to claim 1 , wherein the control circuit includes an operational amplifier.

5. A magnetic memory device comprising:

a first MOSFET having one terminal which receives a constant current, and a gate terminal connected to said one terminal;

a second MOSFET having one terminal connected to a sense amplifier, and a gate terminal which receives the same potential as a potential at the gate terminal of the first MOSFET;

a first magnetoresistive element which is connected the other terminal of the second MOSFET, takes a high-resistance state when receiving a write current in a first direction, takes a low-resistance state having a resistance value lower than a resistance value in the high-resistance state when receiving a write current in a second direction opposite to the first direction, and receives a read current in a read operation; and

a second magnetoresistive element which is connected to the other terminal of the first MOSFET, takes one of the high-resistance state and the low-resistance state in accordance with a magnetization state thereof, is fixed to the low-resistance state when a direction of the read current is the same as the first direction, and is fixed to the high-resistance state when the direction of the read current is the same as the second direction.

6. The device according to claim 5 , wherein the first magnetoresistive element and the second magnetoresistive element have combinations of identical films, and have the same shape.

7. The device according to claim 5 , wherein the first magnetoresistive element and the second magnetoresistive element include a fixed layer made of a ferromagnetic material, an interlayer made of a nonmagnetic material, and a free layer made of a ferromagnetic material.

8. The device according to claim 5 , wherein the first MOSFET and the second MOSFET have the same current drivability.

9. A magnetic memory device comprising:

an operational amplifier having a non-inverting input terminal which receives a constant voltage;

a first MOSFET connected to an inverting input terminal of the operational amplifier, and having a gate connected to an output terminal of the operational amplifier;

a second MOSFET having one terminal connected to a sense amplifier, and a gate terminal connected to the output terminal of the operational amplifier;

a first magnetoresistive element which is connected the other terminal of the second MOSFET, takes a high-resistance state when receiving a write current in a first direction, takes a low-resistance state having a resistance value lower than a resistance value in the high-resistance state when receiving a write current in a second direction opposite to the first direction, and receives a read current in a read operation; and

a second magnetoresistive element which is connected to the other terminal of the first MOSFET, takes one of the high-resistance state and the low-resistance state in accordance with a magnetization state thereof, is fixed to the low-resistance state when a direction of the read current is the same as the first direction, and is fixed to the high-resistance state when the direction of the read current is the same as the second direction.

10. The device according to claim 9 , wherein the first magnetoresistive element and the second magnetoresistive element have combinations of identical films, and have the same shape.

11. The device according to claim 9 , wherein the first magnetoresistive element and the second magnetoresistive element include a fixed layer made of a ferromagnetic material, an interlayer made of a nonmagnetic material, and a free layer made of a ferromagnetic material.

12. The device according to claim 9 , wherein the first MOSFET and the second MOSFET have the same current drivability.