Read out scheme for several bits in a single MRAM soft layer
US7187576B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 25, 2004 |
| Grant date | Mar 6, 2007 |
| Priority date | — |
| Expiry date | Apr 7, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C2211/5634
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A magnetic tunnel junction (MTJ) device is configured to store at least two bits of data in a single cell utilizing the variable resistance characteristic of a MTJ. The MTJ includes a soft and two fixed magnetic layers with fixed field directions oriented in perpendicular directions. The soft magnetic layer is separated from the fixed layers by insulating layers preferably with different thicknesses, or with different material compositions. The resulting junction resistance can exhibit at least four distinct resistance values dependent on the magnetic orientation of the free magnetic layer. The cell is configured using a pattern with four lobes to store two bits, and eight lobes to store three bits. The resulting cell can be used to provide a fast, non-volatile magnetic random access memory (MRAM) with high density and no need to rewrite stored data after they are read, or as a fast galvanic isolator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.