Magnetic Tunnel Junctions Based on Out-of-Plane Anisotropy Free and In-Plane Pinned Layer Structures for Magnetic Field Sensors

Abstract

We have studied hysteresis, nonlinearity and sensitivity of CoFeB-MgO based magnetic tunnel junctions with out-of-plane and in-plane magnetizations configuration in the CoFeB free and reference layers. The configuration was achieved by using perpendicular interface anisotropy in the free and exchange bias structure in the pinned layers. For the CoFeB thickness range from 1.05 to 1.4 nm the junctions show linear transfer curves. In this CoFeB thickness range devices show linear range from ± 3 Oe to ± 1 kOe, hysteresis better than 0.6 Oe, nonlinearity 1% of the full scale and sensitivity in the range from 0.0045%/Oe to 3.8%/Oe.