Abstract
This invention provides a spin-orbit torque magnetoresistive random-access memory (SOT-MRAM), which comprises a substrate, and a spin-orbit torque memory cell disposed over the substrate and having a magnetic free layer. The magnetic free layer has at least one of first metallic film exhibiting ferromagnetic and at least one of second metallic film exhibiting spin Hall Effect and connected with the first metallic film. The first metallic film has a thickness sufficient to obtain a ratio for the magnetic free layer ranging from -0.9 to +0.9. The ratio is a remanent magnetization to a saturated magnetization of the magnetic free layer, and is obtained under providing and releasing in turn a first applied magnetic field to the magnetic free layer along with a hard axis of the first metallic film, such that the first metallic film can have multi-level domains when the magnetic free layer is provided with a second applied magnetic field far lower than the first applied magnetic field about the hard axis of the first metallic film and an AC-pulse-electric signal greater than a critical current density generated therefrom. This invention also provides a method for writing the SOT-MRAM stated above.