Abstract: A magnetic tunnel junction (MTJ) structure is of the type having a tunnel barrier positioned between a fixed ferromagnetic layer and a free ferromagnetic layer, the tunnel barrier includes a first barrier layer contacting either the fixed ferromagnetic layer or the free ferromagnetic layer. The first barrier layer transmits a high spin polarization and is selected from the group consisting of metal oxides, metal nitrides, and metal oxynitrides. The second barrier layer, which contacts the first barrier layer, has a low barrier height and is selected from the group consisting of metal oxides, metal nitrides, and metal oxynitrides.

Abstract: A two-axis, single-chip external magnetic field sensor incorporates tunneling magneto-resistance (TMR) technology. In one embodiment, an integrated device includes at least two sensor elements having pinned layers with orientation situated at a known angle (e.g., 90 degrees) with respect to each other. In the presence of a magnetic field, the information from the multiple sensor elements can be processed (e.g., using a conventional bridge configuration) to determine the orientation of the integrated sensor with respect to the external field. In order to achieve an integrated sensor with multiple pinned layer orientations, a novel processing method utilizes antiferromagnetic pinning layers different materials with different blocking temperatures (e.g., PtMn and IrMn).