Storage device and storage method thereof

The invention discloses a storage device and a storage method thereof. The device includes a first magnetic layer, an isolation layer, a second magnetic layer, a third magnetic layer, and a fourth magnetic layer. The isolation layer, the second magnetic layer, and the third magnetic layer are arranged on the first magnetic layer, the second magnetic layer and the third magnetic layer are arranged at the two ends of the first magnetic layer, the isolation layer is arranged between the second isolation magnetic layer and the third magnetic layer, the fourth magnetic layer is arranged on the isolation layer, the second magnetic layer and the third magnetic layer form a first pinned area and a second pinned area at the two ends of the first magnetic layer, the magnetized direction of the first pinned area is same to the magnetized direction of the fourth magnetic layer, and the magnetized direction of the second pinned area is opposite to the magnetized direction of the fourth magnetic layer. The storage device can effectively reduce the critical current density of the magnetized overturning of an MTJ structure free layer and has important meanings in the development of spintronics in the foundation and application aspects.