US Patent 11387405 Resonance rotating spin-transfer torque memory device

A memory device includes a plurality of layers forming a stack. The plurality of layers include a spin polarization layer having a magnetic anisotropy approximately perpendicular to a plane of the spin polarization layer, an antiferromagnetic layer having an antiferromagnetic material, a ferromagnetic layer that is exchange coupled to the antiferromagnetic layer, where the antiferromagnetic layer is between the ferromagnetic layer and the spin polarization layer, and a storage layer having a magnetization direction that indicates a memory state of the storage layer. The memory state is switched by an amount of current through the stack. The spin polarization layer, the ferromagnetic layer, and the antiferromagnetic layer are configured to reduce the amount of current through the stack for switching the magnetization direction of the storage layer relative to an amount of current through a memory device without the spin polarization layer, the ferromagnetic layer, and the antiferromagnetic layer.