Magnetic tunnel junction device with nonferromagnetic interface layer for improved magnetic field response
US5764567A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 27, 1996 |
| Grant date | Jun 9, 1998 |
| Priority date | — |
| Expiry date | Nov 27, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F41/325
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A magnetic tunnel junction device, usable as a memory cell or an external magnetic field sensor, has a tunneling magnetoresistance response, as a function of applied magnetic field, that is substantially symmetric about zero field. The magnetic tunnel junction is made up of two ferromagnetic layers, one of which has its magnetic moment fixed and the other of which has its magnetic moment free to rotate, an insulating tunnel barrier layer between the ferromagnetic layers for permitting tunneling current perpendicularly through the layers, and a nonferromagnetic layer located at the interface between the tunnel barrier layer and one of the ferromagnetic layers. The nonferromagnetic layer increases the spacing between the tunnel barrier layer and the ferromagnetic layer at the interface and thus reduces the magnetic coupling between the fixed and free ferromagnetic layers, which has been determined to be the cause of unsymmetric tunneling magnetoresistance response about zero field. Even though the nonferromagnetic interface layer presents nonspin-polarized electronic states at the tunnel barrier layer interface, it unexpectedly does not cause a suppression of the tunneling magnetores…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.