Abstract
A multi-state MRAM device comprises N overlapping ovals defining a free ferromagnetic region. The size of the free ferromagnetic region is controlled the shape anisotropy of the configuration via at least a aspect ratio greater than 2, of the free ferromagnetic region. The free ferromagnetic region has a magnetic moment spontaneously aligned along the long axis in each oval outside the center region. A center magnetic moment has a multitude of exactly 2* N stable orientations determined by the magnetic moments in the segments of the ovals outside the center region. An embodiment is an MRAM device using tunneling junctions to achieve a multi-state memory configuration. Certain embodiments includes an electrically conducting heavy-metal layer disposed adjacent to and connected with the free ferromagnetic region. Some embodiments include a topological insulating material, such as Bi2Se3
| Original language | English |
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| Patent number | US10204678B2 |
| State | Published - 12 Feb 2019 |