Magnetic random access memory cell with a dual junction for ternary content addressable memory applications

摘要

A MRAM cell including a first tunnel barrier layer between a soft ferromagnetic layer having a free magnetization and a first hard ferromagnetic layer having a first storage magnetization. A second tunnel barrier layer is between the soft ferromagnetic layer and a second hard ferromagnetic layer and has a second storage magnetization. The first storage magnetization is freely orientable at a first high predetermined temperature threshold and the second storage magnetization being freely orientable at a second predetermined high temperature threshold. The first high predetermined temperature threshold is higher than the second predetermined high temperature threshold. The MRAM cell can be used as a ternary content addressable memory (TCAM) and store up to three distinct state levels. The MRAM cell has a reduced size and can be made at low cost.

主权项

1. A method for reading a MRAM cell including a magnetic element comprising a soft ferromagnetic layer having a magnetization that can be freely aligned; a first hard ferromagnetic layer having a first storage magnetization; a first tunnel barrier layer comprised between the soft ferromagnetic layer and the a first hard ferromagnetic layer; a second hard ferromagnetic layer having a second storage magnetization; and a second tunnel barrier layer comprised between the soft ferromagnetic layer and the second hard ferromagnetic layer; the first storage magnetization being be freely orientable at a first high predetermined temperature threshold and the second storage magnetization being freely orientable at a second predetermined high temperature threshold; the first high predetermined temperature threshold being higher than the second predetermined high temperature threshold; the method comprising:
measuring an initial resistance value of the magnetic element with the stored data; providing a first search data to the sense layer and determining the matching between the first search data and the stored data; and providing a second search data to the sense layer and determining the matching between the second search data and the stored data.