US Patent 10032978 MRAM with reduced stray magnetic fields

A magnetoresistive random-access memory (MRAM) is disclosed. The MRAM device reduces stray magnetic fields generated by magnetic layers of the stack, including a reference layer and magnetic layers of the synthetic antiferromagnetic layer, in a way that reduces their impact on the other layers of the stack, including a free layer and an optional filter layer, which may include a polarizer layer or a precessional spin current magnetic layer. The reduction in stray magnetic fields in the stack increases the electrical and retention performance of the stack by reducing switching asymmetry in the free layer. The reduction in stray magnetic fields also may improve performance of a filter layer, such as a precessional spin current magnetic layer by reducing asymmetry in the dynamic magnetic rotation of that layer.