Magnetic random access memory based on the ferromagnetic film with biaxial anisotropy using spin-orbit torque
View Patent ↗A magnetic random access memory (MRAM) device includes a substrate and a ferromagnetic layer formed on the substrate, and the ferromagnetic layer has biaxial anisotropy. Information stores in a cell only with current pulses, which switches magnetization between easy-axes, because spin-orbit field component along easy axes changes with current direction. This leads to an increase in the operating efficiency of the memory device.
1 . A magnetic random access memory (MRAM) device comprising:
a substrate; and
a ferromagnetic layer formed on the substrate,
wherein the ferromagnetic layer has non-centrosymmetric crystal structure and biaxial in-plane anisotropy, and
wherein during a write operation, a magnetization state of the ferromagnetic layer is switched by spin-orbit torque generated by a current applied to the ferromagnetic layer anisotropy.
2 . The MRAM device of claim 1 , wherein the ferromagnetic layer includes gallium manganese arsenide (GaMnAs) or manganese bismuth (MnBi).
3 . The MRAM device of claim 1 , wherein, during the write operation, a current in a first direction is applied to the ferromagnetic layer so that the magnetization state of the ferromagnetic layer switches from a first magnetization state to a second magnetization state.
4 . The MRAM device of claim 3 , wherein, during the write operation, a current in a second direction that is opposite to the first direction is applied to the ferromagnetic layer so that the magnetization state of the ferromagnetic layer switches from the second magnetization to the first magnetization state.
5 . The MRAM device of claim 1 , wherein, during a read operation, information stored in the MRAM device is identified based on a planar Hall resistance value of the ferromagnetic layer.