Multi-state magnetic memory device
US10204678B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Mar 22, 2017 |
| Grant date | Feb 12, 2019 |
| Priority date | — |
| Expiry date | Mar 22, 2037 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10N50/10
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
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. Magnetic moment reversal in the ovals may be determined by spin-transfer torque associated with the electrically conducting layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.